<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2023 Workiva-->
<!--r:2447a25f-7ca0-4234-9730-74bac1a68624,g:ef2affcd-5b26-46ef-99ac-7a0fb5ceaaad-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.crl.com/role/CONSOLIDATEDSTATEMENTSOFINCOME" xlink:type="simple" xlink:href="crl-20221231.xsd#CONSOLIDATEDSTATEMENTSOFINCOME"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/CONSOLIDATEDSTATEMENTSOFINCOME" xlink:type="extended" id="ibde81e1312fe4c2ea79086f2fc281e86_CONSOLIDATEDSTATEMENTSOFINCOME">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b8561304-d757-4cd9-bf74-561b4d52bfb7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b8561304-d757-4cd9-bf74-561b4d52bfb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_49626fe7-8691-4516-8306-549a562f170d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_49626fe7-8691-4516-8306-549a562f170d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_5d325a92-4a3e-43bd-9c09-976c20cb864b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_49626fe7-8691-4516-8306-549a562f170d" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_5d325a92-4a3e-43bd-9c09-976c20cb864b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_64c43f3c-b05b-4f0d-b5d0-d0f66d3e282e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_49626fe7-8691-4516-8306-549a562f170d" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_64c43f3c-b05b-4f0d-b5d0-d0f66d3e282e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_2313d9eb-5a80-431c-aa22-40fa9bb978a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_49626fe7-8691-4516-8306-549a562f170d" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_2313d9eb-5a80-431c-aa22-40fa9bb978a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_09bdd811-ec1a-4b8a-9b68-c4824867f0b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_OperatingIncomeLoss_09bdd811-ec1a-4b8a-9b68-c4824867f0b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_d88c7b88-034d-4b10-8e9a-7b4035423d91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_d88c7b88-034d-4b10-8e9a-7b4035423d91" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_dfa7eeb7-e100-4f01-8a98-39adc993be16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_d88c7b88-034d-4b10-8e9a-7b4035423d91" xlink:to="loc_us-gaap_InvestmentIncomeInterest_dfa7eeb7-e100-4f01-8a98-39adc993be16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_6551824e-086e-452f-89f0-9fe3f9e1a7e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_d88c7b88-034d-4b10-8e9a-7b4035423d91" xlink:to="loc_us-gaap_InterestExpense_6551824e-086e-452f-89f0-9fe3f9e1a7e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_3d99b417-025e-4eb4-a1ed-ebd3393bfc52" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_d88c7b88-034d-4b10-8e9a-7b4035423d91" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_3d99b417-025e-4eb4-a1ed-ebd3393bfc52" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_21662920-7098-4690-bf2f-37c07fc78dd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_21662920-7098-4690-bf2f-37c07fc78dd7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_30e4f390-2259-4109-80a9-6a2179ffeebe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_30e4f390-2259-4109-80a9-6a2179ffeebe" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_eb552be3-397f-471f-b10c-5deb56197e9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_ProfitLoss_eb552be3-397f-471f-b10c-5deb56197e9f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_66299b28-4969-44a5-89ab-17389c81939b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_66299b28-4969-44a5-89ab-17389c81939b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_6a1325c8-2fcd-46d6-95d8-b55ef0c92510" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_NetIncomeLoss_6a1325c8-2fcd-46d6-95d8-b55ef0c92510" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_ad92ca3c-fc79-4798-9954-90f16ee231c7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_EarningsPerShareAbstract_ad92ca3c-fc79-4798-9954-90f16ee231c7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_7178d35e-2805-48f0-81c4-4dff2827e8f1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_ad92ca3c-fc79-4798-9954-90f16ee231c7" xlink:to="loc_us-gaap_EarningsPerShareBasic_7178d35e-2805-48f0-81c4-4dff2827e8f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_4c5cbe8f-8d52-4ebd-8c8c-eaceaca66156" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_ad92ca3c-fc79-4798-9954-90f16ee231c7" xlink:to="loc_us-gaap_EarningsPerShareDiluted_4c5cbe8f-8d52-4ebd-8c8c-eaceaca66156" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_4ffc1018-01fd-4a36-a4dd-ec39b9961adc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_4ffc1018-01fd-4a36-a4dd-ec39b9961adc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_7d617674-ee36-4ce7-a9f0-750a66e1eba1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_4ffc1018-01fd-4a36-a4dd-ec39b9961adc" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_7d617674-ee36-4ce7-a9f0-750a66e1eba1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_03000a9b-9cb7-4ab9-9e80-24fd34f80c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract_4ffc1018-01fd-4a36-a4dd-ec39b9961adc" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_03000a9b-9cb7-4ab9-9e80-24fd34f80c4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_65c8b214-0968-4c7b-8438-3881c1abf1cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_8035edb9-e053-4d37-897e-46ab8bb58e9a" xlink:to="loc_us-gaap_StatementTable_65c8b214-0968-4c7b-8438-3881c1abf1cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_978affae-77f1-49db-98b0-90abf25c4968" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_65c8b214-0968-4c7b-8438-3881c1abf1cd" xlink:to="loc_srt_ProductOrServiceAxis_978affae-77f1-49db-98b0-90abf25c4968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_978affae-77f1-49db-98b0-90abf25c4968_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_978affae-77f1-49db-98b0-90abf25c4968" xlink:to="loc_srt_ProductsAndServicesDomain_978affae-77f1-49db-98b0-90abf25c4968_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b4a757a4-978e-4a2d-83d6-51743e6692a0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_978affae-77f1-49db-98b0-90abf25c4968" xlink:to="loc_srt_ProductsAndServicesDomain_b4a757a4-978e-4a2d-83d6-51743e6692a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_73bf478d-8d48-44d2-9b0b-03bcc0b8f5f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b4a757a4-978e-4a2d-83d6-51743e6692a0" xlink:to="loc_us-gaap_ServiceMember_73bf478d-8d48-44d2-9b0b-03bcc0b8f5f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_68193694-f712-4933-a3a7-b701062c24ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b4a757a4-978e-4a2d-83d6-51743e6692a0" xlink:to="loc_us-gaap_ProductMember_68193694-f712-4933-a3a7-b701062c24ad" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY" xlink:type="simple" xlink:href="crl-20221231.xsd#CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY" xlink:type="extended" id="i9242feea704a4f06ac8cb963e3c4fbaa_CONSOLIDATEDSTATEMENTSOFCHANGESINEQUITY">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_3825cece-c6ce-4c10-a704-4e59cf790578" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3825cece-c6ce-4c10-a704-4e59cf790578" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_707564ca-a95a-4604-9d09-2e0713479597" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_707564ca-a95a-4604-9d09-2e0713479597" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1c60e234-56db-4695-936a-8d16849a13da" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_1c60e234-56db-4695-936a-8d16849a13da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_466e2952-a2b0-499e-abe9-9affd05d6605" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_TreasuryStockCommonShares_466e2952-a2b0-499e-abe9-9affd05d6605" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_NetIncomeLossIncludingPortionAttributabletoNoncontrollingInterestandExcludingRedeemableNoncontrollingInterest_41b0f5ce-90a2-426f-bc8a-97ab2cc67fb0" xlink:href="crl-20221231.xsd#crl_NetIncomeLossIncludingPortionAttributabletoNoncontrollingInterestandExcludingRedeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_crl_NetIncomeLossIncludingPortionAttributabletoNoncontrollingInterestandExcludingRedeemableNoncontrollingInterest_41b0f5ce-90a2-426f-bc8a-97ab2cc67fb0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherComprehensiveIncomeLossIncludingPortionAttributableToNoncontrollingInterestAndExcludingRedeemableNoncontrollingInterestNetOfTax_0b97ffa2-84fd-45af-bd42-8b1fc940077a" xlink:href="crl-20221231.xsd#crl_OtherComprehensiveIncomeLossIncludingPortionAttributableToNoncontrollingInterestAndExcludingRedeemableNoncontrollingInterestNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_crl_OtherComprehensiveIncomeLossIncludingPortionAttributableToNoncontrollingInterestAndExcludingRedeemableNoncontrollingInterestNetOfTax_0b97ffa2-84fd-45af-bd42-8b1fc940077a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_6675e469-1958-455a-ad51-db0da55e5252" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_6675e469-1958-455a-ad51-db0da55e5252" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_bce73ec5-5986-4c00-8e57-9a8ada91c5da" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromRedemptions_bce73ec5-5986-4c00-8e57-9a8ada91c5da" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock_8de3fc0f-4366-4ed8-8c68-bdbc5a74ff95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalIncreaseInCarryingAmountOfRedeemablePreferredStock_8de3fc0f-4366-4ed8-8c68-bdbc5a74ff95" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_865517cf-6689-4013-97d9-a5d0491c38c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_865517cf-6689-4013-97d9-a5d0491c38c8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_db29f4a3-e8a3-4207-85b6-68e696260ad5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_db29f4a3-e8a3-4207-85b6-68e696260ad5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_f42b43d0-12f4-4ff4-a4c1-82d95a5046c6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_f42b43d0-12f4-4ff4-a4c1-82d95a5046c6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_be9f1194-e59b-4e70-8e4f-874a1d43053f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_be9f1194-e59b-4e70-8e4f-874a1d43053f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesRetired_fe679426-f994-408f-aed3-32d96e1122b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockSharesRetired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_TreasuryStockSharesRetired_fe679426-f994-408f-aed3-32d96e1122b4" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_ed9c151a-d0a9-4598-991d-da0815b47c87" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockRetiredCostMethodAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_TreasuryStockRetiredCostMethodAmount_ed9c151a-d0a9-4598-991d-da0815b47c87" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3698b914-fe82-413b-b7e7-23ea8249a140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_8202c0b4-cddd-40cf-a21d-186c9388f778" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3698b914-fe82-413b-b7e7-23ea8249a140" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_6163cd74-bf18-4a3f-aff7-4a1a76610dd0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a3aaad58-938c-4418-9b0f-b83f6b08df71" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3825cece-c6ce-4c10-a704-4e59cf790578" xlink:to="loc_us-gaap_StatementTable_a3aaad58-938c-4418-9b0f-b83f6b08df71" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a3aaad58-938c-4418-9b0f-b83f6b08df71" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3" xlink:to="loc_us-gaap_EquityComponentDomain_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_8b0cdc6b-9e9d-4d6a-beb7-62ee956d3eb3" xlink:to="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_fb9d66d2-7d69-45de-b475-439f597b6c45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_CommonStockMember_fb9d66d2-7d69-45de-b475-439f597b6c45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_14c64398-d9a6-4ea9-b90a-16e0fd9cd827" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_14c64398-d9a6-4ea9-b90a-16e0fd9cd827" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_12273e99-8636-49ba-83c1-d989f4a0dbf1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_RetainedEarningsMember_12273e99-8636-49ba-83c1-d989f4a0dbf1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f81c87da-0eee-4822-8fa8-aeed99ac1787" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f81c87da-0eee-4822-8fa8-aeed99ac1787" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_47fca0be-3b2a-4ffd-8258-974a47326843" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_TreasuryStockCommonMember_47fca0be-3b2a-4ffd-8258-974a47326843" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TotalEquityAttributabletoCommonShareholdersMember_c7b751cb-a1d4-421b-b4ab-31534fa9a175" xlink:href="crl-20221231.xsd#crl_TotalEquityAttributabletoCommonShareholdersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_crl_TotalEquityAttributabletoCommonShareholdersMember_c7b751cb-a1d4-421b-b4ab-31534fa9a175" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_7154913c-e32c-4304-89f7-70560f333b20" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_167f867b-ffae-4e65-a65b-376aa3cd5d14" xlink:to="loc_us-gaap_NoncontrollingInterestMember_7154913c-e32c-4304-89f7-70560f333b20" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails" xlink:type="extended" id="i851094ad008f4847a5d944a511ecc714_DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_eff22e9d-3b53-4bfd-82c9-93694793b37e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_NumberOfReportableSegments_eff22e9d-3b53-4bfd-82c9-93694793b37e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_9fa82e05-289c-4955-8f78-e55f53ea29f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_Depreciation_9fa82e05-289c-4955-8f78-e55f53ea29f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_e1e2e6d7-4e16-4260-9581-4236eddf0e2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_e1e2e6d7-4e16-4260-9581-4236eddf0e2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LifeSettlementContractsInvestmentMethodNumberOfContracts_6925e527-ca8f-4b40-96d1-fddf5a1e08cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LifeSettlementContractsInvestmentMethodNumberOfContracts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_LifeSettlementContractsInvestmentMethodNumberOfContracts_6925e527-ca8f-4b40-96d1-fddf5a1e08cf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LifeSettlementContractsInvestmentMethodFaceValue_c26c5de3-40ef-4d38-a3d6-a80ffdef5487" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LifeSettlementContractsInvestmentMethodFaceValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_LifeSettlementContractsInvestmentMethodFaceValue_c26c5de3-40ef-4d38-a3d6-a80ffdef5487" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_43deeab6-0576-4299-8801-70b942c34809" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_43deeab6-0576-4299-8801-70b942c34809" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RevenueFromContractWithCustomerPaymentTerms_441a3408-800d-4ac7-8f18-688bce476d7d" xlink:href="crl-20221231.xsd#crl_RevenueFromContractWithCustomerPaymentTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_crl_RevenueFromContractWithCustomerPaymentTerms_441a3408-800d-4ac7-8f18-688bce476d7d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_ea2336a7-5893-4927-b2a9-ff86c1499564" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_a7ddfd93-0fc6-425a-8382-6e18ad40a29b" xlink:to="loc_us-gaap_DebtInstrumentTable_ea2336a7-5893-4927-b2a9-ff86c1499564" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_09b41bcb-0900-417d-a278-fc28b08849dc" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ea2336a7-5893-4927-b2a9-ff86c1499564" xlink:to="loc_srt_RangeAxis_09b41bcb-0900-417d-a278-fc28b08849dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_09b41bcb-0900-417d-a278-fc28b08849dc_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_09b41bcb-0900-417d-a278-fc28b08849dc" xlink:to="loc_srt_RangeMember_09b41bcb-0900-417d-a278-fc28b08849dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a86f9e9a-1657-424d-9f84-db16e14aedf0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_09b41bcb-0900-417d-a278-fc28b08849dc" xlink:to="loc_srt_RangeMember_a86f9e9a-1657-424d-9f84-db16e14aedf0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0f31e0b1-9fec-4a5a-8dc7-d5c551052eb1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_a86f9e9a-1657-424d-9f84-db16e14aedf0" xlink:to="loc_srt_MinimumMember_0f31e0b1-9fec-4a5a-8dc7-d5c551052eb1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_57bb7f1b-4e91-406c-9907-4bdb7d246bf1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_a86f9e9a-1657-424d-9f84-db16e14aedf0" xlink:to="loc_srt_MaximumMember_57bb7f1b-4e91-406c-9907-4bdb7d246bf1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ea2336a7-5893-4927-b2a9-ff86c1499564" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_6d651298-9b4b-4aa5-b8a2-0d1e25b6f982" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_9a11e1b6-20bd-4197-a043-ad62c1f5ca8c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_6d651298-9b4b-4aa5-b8a2-0d1e25b6f982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VentureCapitalFundsInvestmentsMember_148b460d-6060-4e03-ad6c-8bb23d0210e7" xlink:href="crl-20221231.xsd#crl_VentureCapitalFundsInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_6d651298-9b4b-4aa5-b8a2-0d1e25b6f982" xlink:to="loc_crl_VentureCapitalFundsInvestmentsMember_148b460d-6060-4e03-ad6c-8bb23d0210e7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESCompositionofPropertyPlantandEquipmentNetDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESCompositionofPropertyPlantandEquipmentNetDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESCompositionofPropertyPlantandEquipmentNetDetails" xlink:type="extended" id="i0b764e16d7f94e53b526024358c46c4b_DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESCompositionofPropertyPlantandEquipmentNetDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0aedfc21-c4d5-4375-bd45-a2d0ed0461b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_2342bd1c-94dd-4610-af8d-163c5bd5f140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0aedfc21-c4d5-4375-bd45-a2d0ed0461b5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_2342bd1c-94dd-4610-af8d-163c5bd5f140" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_d3035300-7240-4168-9e70-1823b5f68669" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0aedfc21-c4d5-4375-bd45-a2d0ed0461b5" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_d3035300-7240-4168-9e70-1823b5f68669" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_bcae2202-f2ba-4a7c-b379-e79091f0d8ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0aedfc21-c4d5-4375-bd45-a2d0ed0461b5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_bcae2202-f2ba-4a7c-b379-e79091f0d8ec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_8f192e34-0c83-45e9-ae48-fe1ff5b7b076" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0aedfc21-c4d5-4375-bd45-a2d0ed0461b5" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_8f192e34-0c83-45e9-ae48-fe1ff5b7b076" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_8f192e34-0c83-45e9-ae48-fe1ff5b7b076" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f1d5fd47-0ba4-456c-8306-a3a2a0e7317f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_253b853a-aee3-421c-b0b2-9b263bac6477" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_LandMember_253b853a-aee3-421c-b0b2-9b263bac6477" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingMember_dae65dc6-b207-44ad-b397-fa5e2ef67d73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BuildingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_BuildingMember_dae65dc6-b207-44ad-b397-fa5e2ef67d73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_37c06d20-136e-4c57-b82e-a91884add80f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_37c06d20-136e-4c57-b82e-a91884add80f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_316107dd-0e79-4d98-a680-f6cf7777aba7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_316107dd-0e79-4d98-a680-f6cf7777aba7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_92204782-4cad-494f-be8c-2bcb8977b083" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_92204782-4cad-494f-be8c-2bcb8977b083" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_3e8b292a-2dcf-4344-b1d5-7b47abfe11e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_ComputerEquipmentMember_3e8b292a-2dcf-4344-b1d5-7b47abfe11e1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VehiclesMember_0f8c7557-1f26-4966-b3ff-336e6b0803b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VehiclesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_VehiclesMember_0f8c7557-1f26-4966-b3ff-336e6b0803b5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_16aded21-b844-43a5-bc49-bdf709321acd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a019c124-f431-4cb0-89c8-b96092841fc1" xlink:to="loc_us-gaap_ConstructionInProgressMember_16aded21-b844-43a5-bc49-bdf709321acd" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertyPlantandEquipmentUsefulLifeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertyPlantandEquipmentUsefulLifeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertyPlantandEquipmentUsefulLifeDetails" xlink:type="extended" id="i1ad4af5b761c4d0899584d4ca8ef47f2_DESCRIPTIONOFBUSINESSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPropertyPlantandEquipmentUsefulLifeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_f053acc0-f162-4b0e-8405-ea7c33a0a6fd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_96c77058-2552-4941-949f-c48965a79d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_f053acc0-f162-4b0e-8405-ea7c33a0a6fd" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_96c77058-2552-4941-949f-c48965a79d2f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_93f32660-7740-49f1-9c13-1b59000e79fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_f053acc0-f162-4b0e-8405-ea7c33a0a6fd" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_93f32660-7740-49f1-9c13-1b59000e79fc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_93f32660-7740-49f1-9c13-1b59000e79fc" xlink:to="loc_srt_RangeAxis_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1" xlink:to="loc_srt_RangeMember_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3209b731-ebc7-442c-9e81-2a130223409d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c47ea0f7-8fa7-418e-983f-dcb85c56e4b1" xlink:to="loc_srt_RangeMember_3209b731-ebc7-442c-9e81-2a130223409d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6dea576b-7698-4aa9-a6d1-411236930446" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3209b731-ebc7-442c-9e81-2a130223409d" xlink:to="loc_srt_MinimumMember_6dea576b-7698-4aa9-a6d1-411236930446" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_37919096-79fe-4950-a03f-a34030cb7a63" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3209b731-ebc7-442c-9e81-2a130223409d" xlink:to="loc_srt_MaximumMember_37919096-79fe-4950-a03f-a34030cb7a63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9e866736-0df2-47ce-a5d4-7efd89147d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_93f32660-7740-49f1-9c13-1b59000e79fc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9e866736-0df2-47ce-a5d4-7efd89147d0a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9e866736-0df2-47ce-a5d4-7efd89147d0a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9e866736-0df2-47ce-a5d4-7efd89147d0a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_9e866736-0df2-47ce-a5d4-7efd89147d0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_9e866736-0df2-47ce-a5d4-7efd89147d0a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_8751d551-fc53-41ee-b584-baac5341c803" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_8751d551-fc53-41ee-b584-baac5341c803" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_708ee493-6d4a-4285-860e-e86c5acc8c65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_708ee493-6d4a-4285-860e-e86c5acc8c65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_0c64b0a9-e56f-42d7-b16a-52c9ec6820ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_0c64b0a9-e56f-42d7-b16a-52c9ec6820ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_79095073-0e59-4831-b11e-b05bf51bd115" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:to="loc_us-gaap_ComputerEquipmentMember_79095073-0e59-4831-b11e-b05bf51bd115" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VehiclesMember_bbe8dfb5-7974-47c3-89d6-955229ba7a99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VehiclesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_45e8a21b-cfdb-4131-9f0f-fa6baaa24b69" xlink:to="loc_us-gaap_VehiclesMember_bbe8dfb5-7974-47c3-89d6-955229ba7a99" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#ACQUISITIONSANDDIVESTITURESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESNarrativeDetails" xlink:type="extended" id="i99cb70550abb4c3d966ee2ab24c76584_ACQUISITIONSANDDIVESTITURESNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_5c1f136c-fd5a-4a95-b590-85a67efcf722" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_5c1f136c-fd5a-4a95-b590-85a67efcf722" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_fc83874f-fd1d-41a3-a701-4fddcc4bded4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage_fc83874f-fd1d-41a3-a701-4fddcc4bded4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_36bc1e47-8128-47a5-9041-7c7a57a9014e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_36bc1e47-8128-47a5-9041-7c7a57a9014e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_771d60c5-d8d7-4d82-b2e1-6e574fe8a021" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAcquiredFromAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_CashAcquiredFromAcquisition_771d60c5-d8d7-4d82-b2e1-6e574fe8a021" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_66b81820-29f8-422c-b3cb-32b58e50709a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_66b81820-29f8-422c-b3cb-32b58e50709a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_BusinessCombinationConsiderationLiabilityContingentUponFuturePerformance_065de771-b82a-4ba3-add3-2900a5475511" xlink:href="crl-20221231.xsd#crl_BusinessCombinationConsiderationLiabilityContingentUponFuturePerformance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_BusinessCombinationConsiderationLiabilityContingentUponFuturePerformance_065de771-b82a-4ba3-add3-2900a5475511" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_BusinessCombinationValueOfConsiderationNotAcquiredInAcquisition_71900f5d-7017-4222-8386-402eb1d1b21b" xlink:href="crl-20221231.xsd#crl_BusinessCombinationValueOfConsiderationNotAcquiredInAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_BusinessCombinationValueOfConsiderationNotAcquiredInAcquisition_71900f5d-7017-4222-8386-402eb1d1b21b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_BusinessCombinationOwnershipPercentageNotAcquired_6e040b76-a08e-49f6-a927-fedbcede6a38" xlink:href="crl-20221231.xsd#crl_BusinessCombinationOwnershipPercentageNotAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_BusinessCombinationOwnershipPercentageNotAcquired_6e040b76-a08e-49f6-a927-fedbcede6a38" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_d0e4e189-3b0f-4e70-851f-3a5a5c69d4a1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_d0e4e189-3b0f-4e70-851f-3a5a5c69d4a1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_PaymentsToSettlePromissoryNote_31121c53-eaf2-4d4b-a671-d4d9d5779bb1" xlink:href="crl-20221231.xsd#crl_PaymentsToSettlePromissoryNote"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_PaymentsToSettlePromissoryNote_31121c53-eaf2-4d4b-a671-d4d9d5779bb1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentForContingentConsiderationLiabilityOperatingActivities_3ff05fb4-d7fe-4baa-a792-9eb398d70da5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentForContingentConsiderationLiabilityOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_PaymentForContingentConsiderationLiabilityOperatingActivities_3ff05fb4-d7fe-4baa-a792-9eb398d70da5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_f9aab82e-7f08-4282-981f-8f69a4f25b5b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_Goodwill_f9aab82e-7f08-4282-981f-8f69a4f25b5b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_f5908d31-a503-41df-ba2d-c2825e2b52ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_f5908d31-a503-41df-ba2d-c2825e2b52ba" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_8468e794-4b04-4904-8ba3-eeb6e140bf89" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_8468e794-4b04-4904-8ba3-eeb6e140bf89" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_48219f77-60a7-40a5-baa1-f2a4838d0ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_48219f77-60a7-40a5-baa1-f2a4838d0ac6" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_BusinessCombinationIntegrationRelatedCostsandTransactionCosts_ea211d47-7112-48c3-bae2-71314f146964" xlink:href="crl-20221231.xsd#crl_BusinessCombinationIntegrationRelatedCostsandTransactionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_BusinessCombinationIntegrationRelatedCostsandTransactionCosts_ea211d47-7112-48c3-bae2-71314f146964" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsRelatedToPreviousPeriod_b1f21fc0-cf42-4f3d-bb23-220273d1c773" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsRelatedToPreviousPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentsRelatedToPreviousPeriod_b1f21fc0-cf42-4f3d-bb23-220273d1c773" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_9566f6df-4fca-4e95-ab10-a48beea9a48b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_9566f6df-4fca-4e95-ab10-a48beea9a48b" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupIncludingDiscontinuedOperationContingentConsideration_dcb878eb-afee-4f6c-af96-5294dc75704b" xlink:href="crl-20221231.xsd#crl_DisposalGroupIncludingDiscontinuedOperationContingentConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_DisposalGroupIncludingDiscontinuedOperationContingentConsideration_dcb878eb-afee-4f6c-af96-5294dc75704b" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_d9fe63fe-8a7a-4b2c-ab08-ae518d106b27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_d9fe63fe-8a7a-4b2c-ab08-ae518d106b27" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_62fc4ac2-3f44-4dde-8e7d-04ad9aec4020" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_62fc4ac2-3f44-4dde-8e7d-04ad9aec4020" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupIncludingDiscontinuedOperationConsiderationPensionOverFundingAndOtherPostClosingAdjustments_2fd63174-e905-4cb0-b81c-2f31f17a9758" xlink:href="crl-20221231.xsd#crl_DisposalGroupIncludingDiscontinuedOperationConsiderationPensionOverFundingAndOtherPostClosingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_DisposalGroupIncludingDiscontinuedOperationConsiderationPensionOverFundingAndOtherPostClosingAdjustments_2fd63174-e905-4cb0-b81c-2f31f17a9758" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupIncludingDiscontinuedOperationPurchaseObligation_eab483e8-bdd4-480d-8b8e-052dd7ea6dbe" xlink:href="crl-20221231.xsd#crl_DisposalGroupIncludingDiscontinuedOperationPurchaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_crl_DisposalGroupIncludingDiscontinuedOperationPurchaseObligation_eab483e8-bdd4-480d-8b8e-052dd7ea6dbe" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8bc54ce6-9f23-4d76-8972-687c0f5c33e5" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_769f2335-51aa-49e2-aa78-eeca904488d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_769f2335-51aa-49e2-aa78-eeca904488d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_769f2335-51aa-49e2-aa78-eeca904488d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_769f2335-51aa-49e2-aa78-eeca904488d2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_769f2335-51aa-49e2-aa78-eeca904488d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_769f2335-51aa-49e2-aa78-eeca904488d2" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SAMDITechIncMember_d973e9a1-8c9d-477b-8978-df4afe5bb503" xlink:href="crl-20221231.xsd#crl_SAMDITechIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_SAMDITechIncMember_d973e9a1-8c9d-477b-8978-df4afe5bb503" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ExploraBioLabsMember_5cf72321-3cc0-417a-bf33-13147bd58c74" xlink:href="crl-20221231.xsd#crl_ExploraBioLabsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_ExploraBioLabsMember_5cf72321-3cc0-417a-bf33-13147bd58c74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VigeneBiosciencesIncMember_3e8fbdc2-3e27-429c-a4ac-4a4bad398ad2" xlink:href="crl-20221231.xsd#crl_VigeneBiosciencesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_VigeneBiosciencesIncMember_3e8fbdc2-3e27-429c-a4ac-4a4bad398ad2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RetrogenixLimitedMember_15637e40-2454-460e-8c77-88dc09e2c9bb" xlink:href="crl-20221231.xsd#crl_RetrogenixLimitedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_RetrogenixLimitedMember_15637e40-2454-460e-8c77-88dc09e2c9bb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CognateBioServicesIncMember_8f80e40c-74de-45c0-9703-a9a61098e3c2" xlink:href="crl-20221231.xsd#crl_CognateBioServicesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_CognateBioServicesIncMember_8f80e40c-74de-45c0-9703-a9a61098e3c2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DistributedBioIncMember_c6521ed7-4cb0-4db4-8e95-18dd2bd5b0c3" xlink:href="crl-20221231.xsd#crl_DistributedBioIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_DistributedBioIncMember_c6521ed7-4cb0-4db4-8e95-18dd2bd5b0c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherAcquisitionsMember_20c9bf78-261d-49bf-a64e-5dcb78ba959b" xlink:href="crl-20221231.xsd#crl_OtherAcquisitionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_OtherAcquisitionsMember_20c9bf78-261d-49bf-a64e-5dcb78ba959b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CelleroLLCMember_78b1f940-08ff-4eb0-817b-051acd192f4f" xlink:href="crl-20221231.xsd#crl_CelleroLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_CelleroLLCMember_78b1f940-08ff-4eb0-817b-051acd192f4f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_HemaCareCorporationMember_0e9f857c-4319-4a8d-84d5-886f69aaba1c" xlink:href="crl-20221231.xsd#crl_HemaCareCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_HemaCareCorporationMember_0e9f857c-4319-4a8d-84d5-886f69aaba1c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CognateBioServicesIncAndViegeneBiosciencesIncMember_bb65e739-526a-48cd-91ed-221d2302725c" xlink:href="crl-20221231.xsd#crl_CognateBioServicesIncAndViegeneBiosciencesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ad32db1-b8d9-42b0-a965-6b357c9fbc2b" xlink:to="loc_crl_CognateBioServicesIncAndViegeneBiosciencesIncMember_bb65e739-526a-48cd-91ed-221d2302725c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_68e85320-04aa-4d18-934e-6d5c063f4c7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_68e85320-04aa-4d18-934e-6d5c063f4c7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_68e85320-04aa-4d18-934e-6d5c063f4c7a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_68e85320-04aa-4d18-934e-6d5c063f4c7a" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_68e85320-04aa-4d18-934e-6d5c063f4c7a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_154445f6-c6c5-4274-9dfe-7034f13e707d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_68e85320-04aa-4d18-934e-6d5c063f4c7a" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_154445f6-c6c5-4274-9dfe-7034f13e707d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_81187e05-817d-45a1-bc63-3bbec94caf61" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_154445f6-c6c5-4274-9dfe-7034f13e707d" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_81187e05-817d-45a1-bc63-3bbec94caf61" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e2006a15-eca3-4474-bd7d-951bd562ce9f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_srt_RangeAxis_e2006a15-eca3-4474-bd7d-951bd562ce9f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e2006a15-eca3-4474-bd7d-951bd562ce9f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e2006a15-eca3-4474-bd7d-951bd562ce9f" xlink:to="loc_srt_RangeMember_e2006a15-eca3-4474-bd7d-951bd562ce9f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_77487867-382f-40c9-97f0-e7cf826f0841" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e2006a15-eca3-4474-bd7d-951bd562ce9f" xlink:to="loc_srt_RangeMember_77487867-382f-40c9-97f0-e7cf826f0841" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_175c0527-0c23-4369-909c-174a9de0aebd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_77487867-382f-40c9-97f0-e7cf826f0841" xlink:to="loc_srt_MaximumMember_175c0527-0c23-4369-909c-174a9de0aebd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1967ccac-6a94-4a99-86d6-b046a6046136" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1967ccac-6a94-4a99-86d6-b046a6046136" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1967ccac-6a94-4a99-86d6-b046a6046136_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1967ccac-6a94-4a99-86d6-b046a6046136" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_1967ccac-6a94-4a99-86d6-b046a6046136_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_640a6779-59f0-4da9-9cb9-15b0e6d19533" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_1967ccac-6a94-4a99-86d6-b046a6046136" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_640a6779-59f0-4da9-9cb9-15b0e6d19533" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_AvianMember_e4367463-1209-4d2b-8081-3846f118cee7" xlink:href="crl-20221231.xsd#crl_AvianMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_640a6779-59f0-4da9-9cb9-15b0e6d19533" xlink:to="loc_crl_AvianMember_e4367463-1209-4d2b-8081-3846f118cee7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RMSJapanOperationsMember_74e3d0ad-0417-4048-bbe8-750a175c7d52" xlink:href="crl-20221231.xsd#crl_RMSJapanOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_640a6779-59f0-4da9-9cb9-15b0e6d19533" xlink:to="loc_crl_RMSJapanOperationsMember_74e3d0ad-0417-4048-bbe8-750a175c7d52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CDMOSiteMember_86074a89-2f6b-4335-9b5a-faedc78f0170" xlink:href="crl-20221231.xsd#crl_CDMOSiteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_640a6779-59f0-4da9-9cb9-15b0e6d19533" xlink:to="loc_crl_CDMOSiteMember_86074a89-2f6b-4335-9b5a-faedc78f0170" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_33029a61-e295-450e-9098-1cc51d1d5ca0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_33029a61-e295-450e-9098-1cc51d1d5ca0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_33029a61-e295-450e-9098-1cc51d1d5ca0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_33029a61-e295-450e-9098-1cc51d1d5ca0" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_33029a61-e295-450e-9098-1cc51d1d5ca0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_676c80bb-36a5-4227-b0eb-6ddea5e05ac0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_33029a61-e295-450e-9098-1cc51d1d5ca0" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_676c80bb-36a5-4227-b0eb-6ddea5e05ac0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_b08eb2dd-3689-49b8-ab2d-255302c57994" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_676c80bb-36a5-4227-b0eb-6ddea5e05ac0" xlink:to="loc_us-gaap_SubsequentEventMember_b08eb2dd-3689-49b8-ab2d-255302c57994" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_2e4d524a-09e7-41d9-ae06-8432e7730d68" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_423781d0-3c72-4fea-b7c5-6057ed5a5707" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f2edc1f5-43ed-4c5f-96bc-77fc64bd1301" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_423781d0-3c72-4fea-b7c5-6057ed5a5707" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DepreciationAndAmortizationExpenseMember_0f1bf93a-6696-423d-b851-f4e1a218fa02" xlink:href="crl-20221231.xsd#crl_DepreciationAndAmortizationExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_423781d0-3c72-4fea-b7c5-6057ed5a5707" xlink:to="loc_crl_DepreciationAndAmortizationExpenseMember_0f1bf93a-6696-423d-b851-f4e1a218fa02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_a721b0b1-3e7f-4c97-9a90-6cf0a21825b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_423781d0-3c72-4fea-b7c5-6057ed5a5707" xlink:to="loc_us-gaap_InterestExpenseMember_a721b0b1-3e7f-4c97-9a90-6cf0a21825b5" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESPurchasePriceAllocationsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#ACQUISITIONSANDDIVESTITURESPurchasePriceAllocationsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESPurchasePriceAllocationsDetails" xlink:type="extended" id="i315080f2ac774caca3654002817e4bb5_ACQUISITIONSANDDIVESTITURESPurchasePriceAllocationsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_879c97c8-6862-4471-b65c-3a49aa8dc842" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_879c97c8-6862-4471-b65c-3a49aa8dc842" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_2187e1f6-88df-45ab-b1f7-5dc81165af82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_2187e1f6-88df-45ab-b1f7-5dc81165af82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_f299fb5b-d30e-4783-aa1d-2e93d852b3be" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_f299fb5b-d30e-4783-aa1d-2e93d852b3be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_f39dc1af-e966-42b4-98bc-d82ffbd08054" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_f39dc1af-e966-42b4-98bc-d82ffbd08054" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLeaseAssets_e4ab1b62-3a08-4767-a01b-9edbe5db52ba" xlink:href="crl-20221231.xsd#crl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLeaseAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_crl_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLeaseAssets_e4ab1b62-3a08-4767-a01b-9edbe5db52ba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_69c7f234-882c-463b-a83a-7cdee445f273" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_Goodwill_69c7f234-882c-463b-a83a-7cdee445f273" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_89590b6d-3340-48ad-a2c5-9100aa5d55e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_89590b6d-3340-48ad-a2c5-9100aa5d55e7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_8c152ef1-0512-48b6-a06f-2116249103b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_8c152ef1-0512-48b6-a06f-2116249103b4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_f33774d7-78ae-4cb0-8a85-2fa55c7f5632" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue_f33774d7-78ae-4cb0-8a85-2fa55c7f5632" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_52770d76-fd98-47a1-97f7-b6b86f167f3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther_52770d76-fd98-47a1-97f7-b6b86f167f3b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_36044b86-f503-4710-9a03-89bdf2500d36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation_36044b86-f503-4710-9a03-89bdf2500d36" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_86ea6ff5-875a-4ffb-8c03-b7baacd05b3f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_86ea6ff5-875a-4ffb-8c03-b7baacd05b3f" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_a601f811-0b94-457f-9ffe-24527b9e60d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_a601f811-0b94-457f-9ffe-24527b9e60d4" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_68d38f39-6d99-4fc7-9a80-abe5c964a680" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_68d38f39-6d99-4fc7-9a80-abe5c964a680" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_fa747786-0139-47b9-9027-da8aa6201a41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount_fa747786-0139-47b9-9027-da8aa6201a41" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_IndirectTaxContingencyCurrent_865d9086-8255-4325-b676-e9a36536db58" xlink:href="crl-20221231.xsd#crl_IndirectTaxContingencyCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_crl_IndirectTaxContingencyCurrent_865d9086-8255-4325-b676-e9a36536db58" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_GoodwillAcquiredNotDeductibleForIncomeTaxes_89c543e9-e230-4645-a364-140907e65b3d" xlink:href="crl-20221231.xsd#crl_GoodwillAcquiredNotDeductibleForIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_crl_GoodwillAcquiredNotDeductibleForIncomeTaxes_89c543e9-e230-4645-a364-140907e65b3d" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9c813d7-eda4-4ad8-bd3b-fa76989598c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_1289101f-7493-4c66-88f2-e400ccb416fb" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9c813d7-eda4-4ad8-bd3b-fa76989598c5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_214b4243-fb00-4e83-a800-28cf37ab31f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_e9c813d7-eda4-4ad8-bd3b-fa76989598c5" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_214b4243-fb00-4e83-a800-28cf37ab31f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_214b4243-fb00-4e83-a800-28cf37ab31f5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_214b4243-fb00-4e83-a800-28cf37ab31f5" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_214b4243-fb00-4e83-a800-28cf37ab31f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_214b4243-fb00-4e83-a800-28cf37ab31f5" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ExploraBioLabsMember_5cb2d485-6410-44c0-9a7d-42bcc0e76e73" xlink:href="crl-20221231.xsd#crl_ExploraBioLabsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_ExploraBioLabsMember_5cb2d485-6410-44c0-9a7d-42bcc0e76e73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VigeneBiosciencesIncMember_71fab295-d4b8-436f-a35b-fa804d70c0a1" xlink:href="crl-20221231.xsd#crl_VigeneBiosciencesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_VigeneBiosciencesIncMember_71fab295-d4b8-436f-a35b-fa804d70c0a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RetrogenixLimitedMember_103e51b0-6b8d-4a74-89e3-8405cbf14897" xlink:href="crl-20221231.xsd#crl_RetrogenixLimitedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_RetrogenixLimitedMember_103e51b0-6b8d-4a74-89e3-8405cbf14897" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CognateBioServicesIncMember_b1a539fd-dc5b-4418-bf4f-6428ff4f5392" xlink:href="crl-20221231.xsd#crl_CognateBioServicesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_CognateBioServicesIncMember_b1a539fd-dc5b-4418-bf4f-6428ff4f5392" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DistributedBioIncMember_a49e1bb1-ba55-4dcc-981f-cb5253fbc519" xlink:href="crl-20221231.xsd#crl_DistributedBioIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_DistributedBioIncMember_a49e1bb1-ba55-4dcc-981f-cb5253fbc519" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CelleroLLCMember_82a4c0d6-d9ce-46c8-ad5c-0fb5effff42e" xlink:href="crl-20221231.xsd#crl_CelleroLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_CelleroLLCMember_82a4c0d6-d9ce-46c8-ad5c-0fb5effff42e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_HemaCareCorporationMember_0d050bf0-32f0-4cb0-9e8d-6f076a5cd72f" xlink:href="crl-20221231.xsd#crl_HemaCareCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_b3f1da81-472a-4f6d-b200-11fb1df0fbda" xlink:to="loc_crl_HemaCareCorporationMember_0d050bf0-32f0-4cb0-9e8d-6f076a5cd72f" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESDefiniteLivedIntangibleAssetsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#ACQUISITIONSANDDIVESTITURESDefiniteLivedIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESDefiniteLivedIntangibleAssetsDetails" xlink:type="extended" id="i6721cad50a4846faa3008e4e27a8d1c6_ACQUISITIONSANDDIVESTITURESDefiniteLivedIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_59667426-8dcf-4390-882e-a7c19cf87884" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_c29cb77e-d023-4ebe-98ba-59a92f8d59b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_59667426-8dcf-4390-882e-a7c19cf87884" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_c29cb77e-d023-4ebe-98ba-59a92f8d59b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_4eea1b6e-adba-4c8a-ba51-e76a08d5e01b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_59667426-8dcf-4390-882e-a7c19cf87884" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_4eea1b6e-adba-4c8a-ba51-e76a08d5e01b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_c8bca495-2255-49bc-a151-195af1bb389d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_59667426-8dcf-4390-882e-a7c19cf87884" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_c8bca495-2255-49bc-a151-195af1bb389d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_049832b5-f448-49a3-b5f6-7044e97b551b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_c8bca495-2255-49bc-a151-195af1bb389d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_049832b5-f448-49a3-b5f6-7044e97b551b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_049832b5-f448-49a3-b5f6-7044e97b551b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_049832b5-f448-49a3-b5f6-7044e97b551b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_049832b5-f448-49a3-b5f6-7044e97b551b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ff5c6dc5-4f6a-4604-88fb-54760e15d214" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_049832b5-f448-49a3-b5f6-7044e97b551b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ff5c6dc5-4f6a-4604-88fb-54760e15d214" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_eed43bf9-af7b-469b-9e76-9f0034c329eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ff5c6dc5-4f6a-4604-88fb-54760e15d214" xlink:to="loc_us-gaap_CustomerRelationshipsMember_eed43bf9-af7b-469b-9e76-9f0034c329eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_d145760d-30d5-44b8-a0e6-64f18d71c947" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ff5c6dc5-4f6a-4604-88fb-54760e15d214" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_d145760d-30d5-44b8-a0e6-64f18d71c947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_7af8e889-5bf5-4922-93fc-af0e22c57fe9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ff5c6dc5-4f6a-4604-88fb-54760e15d214" xlink:to="loc_us-gaap_TradeNamesMember_7af8e889-5bf5-4922-93fc-af0e22c57fe9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_41308f48-6ccd-422e-ae5e-56e7ce86655b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_c8bca495-2255-49bc-a151-195af1bb389d" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_41308f48-6ccd-422e-ae5e-56e7ce86655b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_41308f48-6ccd-422e-ae5e-56e7ce86655b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_41308f48-6ccd-422e-ae5e-56e7ce86655b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_41308f48-6ccd-422e-ae5e-56e7ce86655b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_41308f48-6ccd-422e-ae5e-56e7ce86655b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ExploraBioLabsMember_74ddfabd-875d-415d-8394-53f4e318edad" xlink:href="crl-20221231.xsd#crl_ExploraBioLabsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_ExploraBioLabsMember_74ddfabd-875d-415d-8394-53f4e318edad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VigeneBiosciencesIncMember_70eafa36-470c-4b73-b752-0560dc8784b8" xlink:href="crl-20221231.xsd#crl_VigeneBiosciencesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_VigeneBiosciencesIncMember_70eafa36-470c-4b73-b752-0560dc8784b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RetrogenixLimitedMember_c274592d-d1b9-487d-8ef9-a7124d4eeb9c" xlink:href="crl-20221231.xsd#crl_RetrogenixLimitedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_RetrogenixLimitedMember_c274592d-d1b9-487d-8ef9-a7124d4eeb9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CognateBioServicesIncMember_c9d8e18a-4012-45c2-be94-091acdc55d90" xlink:href="crl-20221231.xsd#crl_CognateBioServicesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_CognateBioServicesIncMember_c9d8e18a-4012-45c2-be94-091acdc55d90" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DistributedBioIncMember_1a705e09-7202-4517-83e1-b410a46e1169" xlink:href="crl-20221231.xsd#crl_DistributedBioIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_DistributedBioIncMember_1a705e09-7202-4517-83e1-b410a46e1169" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CelleroLLCMember_ebe8b6a5-d772-433f-8696-8744576adf40" xlink:href="crl-20221231.xsd#crl_CelleroLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_CelleroLLCMember_ebe8b6a5-d772-433f-8696-8744576adf40" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_HemaCareCorporationMember_d5305db3-568d-45c3-b79b-ab6b8ed2c0ed" xlink:href="crl-20221231.xsd#crl_HemaCareCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6c9cf1c7-c81b-4a8a-8e03-0380c070997d" xlink:to="loc_crl_HemaCareCorporationMember_d5305db3-568d-45c3-b79b-ab6b8ed2c0ed" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESProFormaFinancialInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#ACQUISITIONSANDDIVESTITURESProFormaFinancialInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESProFormaFinancialInformationDetails" xlink:type="extended" id="i615e2ace42fe4a8b9f7a18eaaeaadf73_ACQUISITIONSANDDIVESTITURESProFormaFinancialInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_4a3a92c6-f7ea-41a7-8ba5-2ab7d1db37b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_6af6a549-a50c-4816-95f2-375ba43a2946" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_4a3a92c6-f7ea-41a7-8ba5-2ab7d1db37b0" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_6af6a549-a50c-4816-95f2-375ba43a2946" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_046a2c2c-2ada-4fc4-90a0-4401e92b11e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_4a3a92c6-f7ea-41a7-8ba5-2ab7d1db37b0" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_046a2c2c-2ada-4fc4-90a0-4401e92b11e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_f92d4fd9-af9d-4bd4-9dbd-4b00d385a918" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_4a3a92c6-f7ea-41a7-8ba5-2ab7d1db37b0" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_f92d4fd9-af9d-4bd4-9dbd-4b00d385a918" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_08d67d61-c432-4a49-b37a-c941c1fbe8bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_f92d4fd9-af9d-4bd4-9dbd-4b00d385a918" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_08d67d61-c432-4a49-b37a-c941c1fbe8bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_08d67d61-c432-4a49-b37a-c941c1fbe8bd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_08d67d61-c432-4a49-b37a-c941c1fbe8bd" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_08d67d61-c432-4a49-b37a-c941c1fbe8bd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8f163c50-b91b-4b91-91ee-1bac770d9965" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_08d67d61-c432-4a49-b37a-c941c1fbe8bd" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8f163c50-b91b-4b91-91ee-1bac770d9965" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CognateBioServicesIncAndViegeneBiosciencesIncMember_6c8637d9-c291-442c-8b5e-0ee3a25d711a" xlink:href="crl-20221231.xsd#crl_CognateBioServicesIncAndViegeneBiosciencesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_8f163c50-b91b-4b91-91ee-1bac770d9965" xlink:to="loc_crl_CognateBioServicesIncAndViegeneBiosciencesIncMember_6c8637d9-c291-442c-8b5e-0ee3a25d711a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESScheduleofDivestituresDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#ACQUISITIONSANDDIVESTITURESScheduleofDivestituresDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/ACQUISITIONSANDDIVESTITURESScheduleofDivestituresDetails" xlink:type="extended" id="i31c580f68562451888b44ea319140564_ACQUISITIONSANDDIVESTITURESScheduleofDivestituresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_b2279d12-86f9-4617-a12a-521402ed2a84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_b2279d12-86f9-4617-a12a-521402ed2a84" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_ea53147a-27c0-4cc3-b986-ca18057d98f4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_ea53147a-27c0-4cc3-b986-ca18057d98f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_9417d218-7994-4607-838e-9eb616a5d2df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_9417d218-7994-4607-838e-9eb616a5d2df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseRightOfUseAssetsNet_be05f186-fc88-4c35-a53e-c358b490122b" xlink:href="crl-20221231.xsd#crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseRightOfUseAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseRightOfUseAssetsNet_be05f186-fc88-4c35-a53e-c358b490122b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_2c7e8799-8ba8-43fc-a817-8fff86ea8984" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1_2c7e8799-8ba8-43fc-a817-8fff86ea8984" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupClientRelationshipsNet_58fe9dcc-5e03-476e-b69b-498cdc2254a6" xlink:href="crl-20221231.xsd#crl_DisposalGroupClientRelationshipsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_crl_DisposalGroupClientRelationshipsNet_58fe9dcc-5e03-476e-b69b-498cdc2254a6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherAssets_915150d0-ab30-44c1-9045-ac67b379f9d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherAssets_915150d0-ab30-44c1-9045-ac67b379f9d4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_285f6e12-1d59-4f99-a625-13c1453100af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationAbstract_aa25ebb4-64e6-496b-8c1b-3f26c91605bb" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_285f6e12-1d59-4f99-a625-13c1453100af" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_b2279d12-86f9-4617-a12a-521402ed2a84" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_66d693c8-09b0-4767-a767-f69304f4243b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_66d693c8-09b0-4767-a767-f69304f4243b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiability_d3718744-1578-4ac1-b09d-3064e852227a" xlink:href="crl-20221231.xsd#crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:to="loc_crl_DisposalGroupIncludingDiscontinuedOperationOperatingLeaseLiability_d3718744-1578-4ac1-b09d-3064e852227a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent_1d093f01-f83d-4598-b9f1-8388bb8c5721" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationNoncurrent_1d093f01-f83d-4598-b9f1-8388bb8c5721" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_383ac9eb-4709-4253-9ca9-b01f69ff18dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationAbstract_31c3e367-375e-4bb8-bc2e-d9ee634c7ef9" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_383ac9eb-4709-4253-9ca9-b01f69ff18dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_23282a91-6cfc-4ba6-b7fe-a7d31cf94cb3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_b2279d12-86f9-4617-a12a-521402ed2a84" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_23282a91-6cfc-4ba6-b7fe-a7d31cf94cb3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_c19fe66f-92f4-410b-985a-1e3febb8dddc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_23282a91-6cfc-4ba6-b7fe-a7d31cf94cb3" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_c19fe66f-92f4-410b-985a-1e3febb8dddc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_c19fe66f-92f4-410b-985a-1e3febb8dddc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_c19fe66f-92f4-410b-985a-1e3febb8dddc" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_c19fe66f-92f4-410b-985a-1e3febb8dddc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_e81165b6-857b-4d6b-b0fe-e8f2098709d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_c19fe66f-92f4-410b-985a-1e3febb8dddc" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_e81165b6-857b-4d6b-b0fe-e8f2098709d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_9f8d2947-7838-40b0-b9a4-3c61666ebfb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_e81165b6-857b-4d6b-b0fe-e8f2098709d6" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_9f8d2947-7838-40b0-b9a4-3c61666ebfb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_23282a91-6cfc-4ba6-b7fe-a7d31cf94cb3" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2eea46c5-a473-4fcc-a286-8aebd9a2f812" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_ba8b2d80-5764-4e9f-8d35-3b2587a8f4ad" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2eea46c5-a473-4fcc-a286-8aebd9a2f812" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_AvianMember_60a9d4f7-0767-4608-a9ee-ab8ce9e0e5b2" xlink:href="crl-20221231.xsd#crl_AvianMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2eea46c5-a473-4fcc-a286-8aebd9a2f812" xlink:to="loc_crl_AvianMember_60a9d4f7-0767-4608-a9ee-ab8ce9e0e5b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RMSJapanOperationsMember_2634655b-f568-4076-bd3d-9e30c03b13f2" xlink:href="crl-20221231.xsd#crl_RMSJapanOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2eea46c5-a473-4fcc-a286-8aebd9a2f812" xlink:to="loc_crl_RMSJapanOperationsMember_2634655b-f568-4076-bd3d-9e30c03b13f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CDMOSiteMember_3a546f8e-d0a8-4e7d-826d-4e1a93607a4f" xlink:href="crl-20221231.xsd#crl_CDMOSiteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2eea46c5-a473-4fcc-a286-8aebd9a2f812" xlink:to="loc_crl_CDMOSiteMember_3a546f8e-d0a8-4e7d-826d-4e1a93607a4f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDisaggregationofRevenuesbyMajorBusinessLineDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#REVENUEFROMCONTRACTSWITHCUSTOMERSDisaggregationofRevenuesbyMajorBusinessLineDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSDisaggregationofRevenuesbyMajorBusinessLineDetails" xlink:type="extended" id="i2ccf650ed70b4277ae1c45d0b04649bb_REVENUEFROMCONTRACTSWITHCUSTOMERSDisaggregationofRevenuesbyMajorBusinessLineDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_66410562-472c-4861-8154-73075d64ec77" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ca4c1d18-f6a3-4541-8748-5fcc620854ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_66410562-472c-4861-8154-73075d64ec77" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_ca4c1d18-f6a3-4541-8748-5fcc620854ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_fbae44c1-cc12-4779-934b-42c0eb7f0de0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_66410562-472c-4861-8154-73075d64ec77" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_fbae44c1-cc12-4779-934b-42c0eb7f0de0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_bdb56f3c-d14a-4212-8f8d-2e6edd737656" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_fbae44c1-cc12-4779-934b-42c0eb7f0de0" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_bdb56f3c-d14a-4212-8f8d-2e6edd737656" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_bdb56f3c-d14a-4212-8f8d-2e6edd737656_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bdb56f3c-d14a-4212-8f8d-2e6edd737656" xlink:to="loc_us-gaap_SegmentDomain_bdb56f3c-d14a-4212-8f8d-2e6edd737656_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_23fb2810-3b61-48a6-88ec-daf272816946" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_bdb56f3c-d14a-4212-8f8d-2e6edd737656" xlink:to="loc_us-gaap_SegmentDomain_23fb2810-3b61-48a6-88ec-daf272816946" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ResearchModelsAndServicesMember_62b1b3a6-6623-4267-b606-6407cfac7247" xlink:href="crl-20221231.xsd#crl_ResearchModelsAndServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_23fb2810-3b61-48a6-88ec-daf272816946" xlink:to="loc_crl_ResearchModelsAndServicesMember_62b1b3a6-6623-4267-b606-6407cfac7247" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DiscoveryandSafetyAssessmentMember_e1aa16eb-d7f6-4c72-a5bb-80845527844f" xlink:href="crl-20221231.xsd#crl_DiscoveryandSafetyAssessmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_23fb2810-3b61-48a6-88ec-daf272816946" xlink:to="loc_crl_DiscoveryandSafetyAssessmentMember_e1aa16eb-d7f6-4c72-a5bb-80845527844f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ManufacturingSupportMember_b7308804-6768-4545-b26d-681c6d68f769" xlink:href="crl-20221231.xsd#crl_ManufacturingSupportMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_23fb2810-3b61-48a6-88ec-daf272816946" xlink:to="loc_crl_ManufacturingSupportMember_b7308804-6768-4545-b26d-681c6d68f769" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_5b16ec13-a79c-4e04-8648-84d39aa2a184" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_fbae44c1-cc12-4779-934b-42c0eb7f0de0" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_5b16ec13-a79c-4e04-8648-84d39aa2a184" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_5b16ec13-a79c-4e04-8648-84d39aa2a184_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_5b16ec13-a79c-4e04-8648-84d39aa2a184" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_5b16ec13-a79c-4e04-8648-84d39aa2a184_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_a9ed20aa-6a02-4db1-afe2-a5c5df8bcd16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_5b16ec13-a79c-4e04-8648-84d39aa2a184" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_a9ed20aa-6a02-4db1-afe2-a5c5df8bcd16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_cc5a00c6-60e4-4ddd-946d-38287ba17d66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_a9ed20aa-6a02-4db1-afe2-a5c5df8bcd16" xlink:to="loc_us-gaap_TransferredOverTimeMember_cc5a00c6-60e4-4ddd-946d-38287ba17d66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_edec1f07-bb62-41d0-918b-8d0a8a74eedd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_a9ed20aa-6a02-4db1-afe2-a5c5df8bcd16" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_edec1f07-bb62-41d0-918b-8d0a8a74eedd" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails" xlink:type="extended" id="i6785c4278d824d2ab12e03939fa9decc_REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ContractWithCustomerUnpaidAdvancedClientBillings_079d129c-bdb4-47c5-a2a4-96b439262208" xlink:href="crl-20221231.xsd#crl_ContractWithCustomerUnpaidAdvancedClientBillings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_crl_ContractWithCustomerUnpaidAdvancedClientBillings_079d129c-bdb4-47c5-a2a4-96b439262208" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_aace2c58-c15d-46c9-b0a4-d1586e4b58aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_aace2c58-c15d-46c9-b0a4-d1586e4b58aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_3e9f8e65-2b44-4523-ad9f-ce8c4ff8154a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_3e9f8e65-2b44-4523-ad9f-ce8c4ff8154a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_21b75f90-5edd-4d5a-bc42-98de0811f385" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_21b75f90-5edd-4d5a-bc42-98de0811f385" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_793ded20-0423-47d5-b564-d39c48367966" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_793ded20-0423-47d5-b564-d39c48367966" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeLeaseRevenue_9a65ca58-5cde-4a26-b544-885cc3797296" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeLeaseRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_SalesTypeLeaseRevenue_9a65ca58-5cde-4a26-b544-885cc3797296" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_d2ed67d6-525c-4a70-b334-7902be869184" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_d2ed67d6-525c-4a70-b334-7902be869184" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_1e247c5b-4335-49a2-8748-b79a6c02a842" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_d2ed67d6-525c-4a70-b334-7902be869184" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_1e247c5b-4335-49a2-8748-b79a6c02a842" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1" xlink:type="simple" xlink:href="crl-20221231.xsd#REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1" xlink:type="extended" id="i03aa2fff0249452e977dc021448eed40_REVENUEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ContractWithCustomerUnpaidAdvancedClientBillings_079d129c-bdb4-47c5-a2a4-96b439262208" xlink:href="crl-20221231.xsd#crl_ContractWithCustomerUnpaidAdvancedClientBillings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_crl_ContractWithCustomerUnpaidAdvancedClientBillings_079d129c-bdb4-47c5-a2a4-96b439262208" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_aace2c58-c15d-46c9-b0a4-d1586e4b58aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_aace2c58-c15d-46c9-b0a4-d1586e4b58aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_3e9f8e65-2b44-4523-ad9f-ce8c4ff8154a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_3e9f8e65-2b44-4523-ad9f-ce8c4ff8154a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_21b75f90-5edd-4d5a-bc42-98de0811f385" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_21b75f90-5edd-4d5a-bc42-98de0811f385" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_793ded20-0423-47d5-b564-d39c48367966" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_793ded20-0423-47d5-b564-d39c48367966" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeLeaseRevenue_9a65ca58-5cde-4a26-b544-885cc3797296" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeLeaseRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_SalesTypeLeaseRevenue_9a65ca58-5cde-4a26-b544-885cc3797296" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_d2ed67d6-525c-4a70-b334-7902be869184" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_3f3d1ac3-3582-456f-b47a-8bfe02488fa9" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_d2ed67d6-525c-4a70-b334-7902be869184" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/SEGMENTANDGEOGRAPHICINFORMATIONFinancialInformationbyReportableBusinessSegmentDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#SEGMENTANDGEOGRAPHICINFORMATIONFinancialInformationbyReportableBusinessSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/SEGMENTANDGEOGRAPHICINFORMATIONFinancialInformationbyReportableBusinessSegmentDetails" xlink:type="extended" id="ie8c2f305b29b4cb9a9951cee6aadb686_SEGMENTANDGEOGRAPHICINFORMATIONFinancialInformationbyReportableBusinessSegmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b5f4beb4-ce58-477c-a467-81b8d549b8e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b5f4beb4-ce58-477c-a467-81b8d549b8e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_7f0dc14a-fd47-4562-9c73-ad6b585d6371" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:to="loc_us-gaap_OperatingIncomeLoss_7f0dc14a-fd47-4562-9c73-ad6b585d6371" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_f77743ae-1349-42a2-8594-c6bdb2fd17ca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_f77743ae-1349-42a2-8594-c6bdb2fd17ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_c210b183-75c6-4f47-a585-13c3db4e7a27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireProductiveAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_c210b183-75c6-4f47-a585-13c3db4e7a27" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_558e8428-3925-45b1-bf4f-279762a97cad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_ed9eece8-7ab0-4a19-8725-337cc91c688a" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_558e8428-3925-45b1-bf4f-279762a97cad" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_75941428-ae6b-4854-84cd-817544ce424b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_558e8428-3925-45b1-bf4f-279762a97cad" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_75941428-ae6b-4854-84cd-817544ce424b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_75941428-ae6b-4854-84cd-817544ce424b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_75941428-ae6b-4854-84cd-817544ce424b" xlink:to="loc_us-gaap_SegmentDomain_75941428-ae6b-4854-84cd-817544ce424b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_8e1acf40-4785-4228-a14d-07f8cebfb3e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_75941428-ae6b-4854-84cd-817544ce424b" xlink:to="loc_us-gaap_SegmentDomain_8e1acf40-4785-4228-a14d-07f8cebfb3e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ResearchModelsAndServicesMember_f3a0af07-ec75-4cb6-b012-b2311784b239" xlink:href="crl-20221231.xsd#crl_ResearchModelsAndServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8e1acf40-4785-4228-a14d-07f8cebfb3e5" xlink:to="loc_crl_ResearchModelsAndServicesMember_f3a0af07-ec75-4cb6-b012-b2311784b239" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DiscoveryandSafetyAssessmentMember_426a40a2-9973-4899-ad76-c047895636f5" xlink:href="crl-20221231.xsd#crl_DiscoveryandSafetyAssessmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8e1acf40-4785-4228-a14d-07f8cebfb3e5" xlink:to="loc_crl_DiscoveryandSafetyAssessmentMember_426a40a2-9973-4899-ad76-c047895636f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ManufacturingSupportMember_56b56278-1daf-4359-a728-e22bd1958816" xlink:href="crl-20221231.xsd#crl_ManufacturingSupportMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8e1acf40-4785-4228-a14d-07f8cebfb3e5" xlink:to="loc_crl_ManufacturingSupportMember_56b56278-1daf-4359-a728-e22bd1958816" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_9c4d3363-b360-4ae8-b90b-d624f5308e5a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_558e8428-3925-45b1-bf4f-279762a97cad" xlink:to="loc_srt_ConsolidationItemsAxis_9c4d3363-b360-4ae8-b90b-d624f5308e5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_9c4d3363-b360-4ae8-b90b-d624f5308e5a_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_9c4d3363-b360-4ae8-b90b-d624f5308e5a" xlink:to="loc_srt_ConsolidationItemsDomain_9c4d3363-b360-4ae8-b90b-d624f5308e5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_0ccb231b-2be0-432e-8747-6b0d73c86702" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_9c4d3363-b360-4ae8-b90b-d624f5308e5a" xlink:to="loc_srt_ConsolidationItemsDomain_0ccb231b-2be0-432e-8747-6b0d73c86702" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_20ff8855-fde3-4a61-a386-29ecbf19778e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_0ccb231b-2be0-432e-8747-6b0d73c86702" xlink:to="loc_us-gaap_OperatingSegmentsMember_20ff8855-fde3-4a61-a386-29ecbf19778e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_7f6a73ba-a9a2-4a8a-bc36-06e661f0f6af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_0ccb231b-2be0-432e-8747-6b0d73c86702" xlink:to="loc_us-gaap_CorporateNonSegmentMember_7f6a73ba-a9a2-4a8a-bc36-06e661f0f6af" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/SEGMENTANDGEOGRAPHICINFORMATIONRevenueandLongLivedAssetsbyGeographicSegmentDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#SEGMENTANDGEOGRAPHICINFORMATIONRevenueandLongLivedAssetsbyGeographicSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/SEGMENTANDGEOGRAPHICINFORMATIONRevenueandLongLivedAssetsbyGeographicSegmentDetails" xlink:type="extended" id="i8991390b108e45fe978858006cd820eb_SEGMENTANDGEOGRAPHICINFORMATIONRevenueandLongLivedAssetsbyGeographicSegmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_64ce0646-eeea-476f-8d9d-ff679417544a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_12cf05ca-6208-4bc6-acd7-ff5beec92095" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_64ce0646-eeea-476f-8d9d-ff679417544a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_12cf05ca-6208-4bc6-acd7-ff5beec92095" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncurrentAssets_c6cee6fa-c5ec-4045-85ad-52f344904cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_64ce0646-eeea-476f-8d9d-ff679417544a" xlink:to="loc_us-gaap_NoncurrentAssets_c6cee6fa-c5ec-4045-85ad-52f344904cb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_713b14e3-fcec-4978-bb41-d6b9caca5073" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_64ce0646-eeea-476f-8d9d-ff679417544a" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_713b14e3-fcec-4978-bb41-d6b9caca5073" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_15e2f5af-38a1-406d-8c13-af5e225cf9ee" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_713b14e3-fcec-4978-bb41-d6b9caca5073" xlink:to="loc_srt_StatementGeographicalAxis_15e2f5af-38a1-406d-8c13-af5e225cf9ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_15e2f5af-38a1-406d-8c13-af5e225cf9ee_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_15e2f5af-38a1-406d-8c13-af5e225cf9ee" xlink:to="loc_srt_SegmentGeographicalDomain_15e2f5af-38a1-406d-8c13-af5e225cf9ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_15e2f5af-38a1-406d-8c13-af5e225cf9ee" xlink:to="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_e3377e39-d015-4655-ac49-28678c5e77a7" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:to="loc_country_US_e3377e39-d015-4655-ac49-28678c5e77a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EuropeMember_f646adc0-1107-4d6f-ac15-f350c585d7af" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EuropeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:to="loc_srt_EuropeMember_f646adc0-1107-4d6f-ac15-f350c585d7af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_03f98f44-c0fc-40d4-b3bf-42a138e89f44" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:to="loc_country_CA_03f98f44-c0fc-40d4-b3bf-42a138e89f44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_00a91038-ec38-4e6c-9ae0-e96e26578974" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:to="loc_srt_AsiaPacificMember_00a91038-ec38-4e6c-9ae0-e96e26578974" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherMember_7540ca04-8a54-4824-b3ab-b3a084f26187" xlink:href="crl-20221231.xsd#crl_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bcfd54c3-c989-4ea8-bc39-ee4d4ca5e66a" xlink:to="loc_crl_OtherMember_7540ca04-8a54-4824-b3ab-b3a084f26187" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSVentureCapitalInvestmentsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSVentureCapitalInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSVentureCapitalInvestmentsDetails" xlink:type="extended" id="i28d4ff76e17b4a6684d2257166f18d18_VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSVentureCapitalInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_a5a5f15b-9a5b-41af-a021-a5fdcc31b460" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_a5a5f15b-9a5b-41af-a021-a5fdcc31b460" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentsCapitalContributions_9bd69787-a8c5-4deb-ae50-05c95c8b81ff" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentsCapitalContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_crl_EquityMethodInvestmentsCapitalContributions_9bd69787-a8c5-4deb-ae50-05c95c8b81ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_0ca63c15-037f-4d63-a4bf-dbe74b9c1764" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_0ca63c15-037f-4d63-a4bf-dbe74b9c1764" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_855f41ab-a088-4a22-acf3-462e18cd9d3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_855f41ab-a088-4a22-acf3-462e18cd9d3b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentCTAAdjustment_0177fdc1-9c24-4a65-96de-c9e7e6d2f0fa" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentCTAAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_crl_EquityMethodInvestmentCTAAdjustment_0177fdc1-9c24-4a65-96de-c9e7e6d2f0fa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_cedd9b82-0e1a-45ef-bdc5-bb579bcb2d01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_fdf5bdd2-4e2e-4e81-b5f1-38163bb720a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_97b3bd06-66c8-4775-b9bb-4acb2c69d5ee" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_fdf5bdd2-4e2e-4e81-b5f1-38163bb720a6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_131eb045-5b25-4d07-9ba8-69c4fd44aed1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_fdf5bdd2-4e2e-4e81-b5f1-38163bb720a6" xlink:to="loc_us-gaap_InvestmentTypeAxis_131eb045-5b25-4d07-9ba8-69c4fd44aed1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_131eb045-5b25-4d07-9ba8-69c4fd44aed1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_131eb045-5b25-4d07-9ba8-69c4fd44aed1" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_131eb045-5b25-4d07-9ba8-69c4fd44aed1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_68241e1f-5b26-45e5-bdd1-a8de2e2af911" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_131eb045-5b25-4d07-9ba8-69c4fd44aed1" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_68241e1f-5b26-45e5-bdd1-a8de2e2af911" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VentureCapitalFundsMember_a3fb285f-db32-4b7c-b4a9-2e9b8c422089" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VentureCapitalFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_68241e1f-5b26-45e5-bdd1-a8de2e2af911" xlink:to="loc_us-gaap_VentureCapitalFundsMember_a3fb285f-db32-4b7c-b4a9-2e9b8c422089" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSStrategicInvestmentsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSStrategicInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSStrategicInvestmentsDetails" xlink:type="extended" id="i383ddb94eb80436c9a6d168de28f842d_VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSStrategicInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_44517144-5924-438d-b456-9e19b12c22bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_us-gaap_EquityMethodInvestments_44517144-5924-438d-b456-9e19b12c22bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_c09f3aa7-e34a-4628-bbce-33bbf5677c4a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_c09f3aa7-e34a-4628-bbce-33bbf5677c4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_c9a2f422-f179-4b6b-96a3-e0b0370c1841" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_c9a2f422-f179-4b6b-96a3-e0b0370c1841" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentOther_92b0fbb8-00ff-48f2-b0e2-701af1432278" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_crl_EquityMethodInvestmentOther_92b0fbb8-00ff-48f2-b0e2-701af1432278" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentCTAAdjustment_5e221bd7-e6ff-419d-bda7-d1df12f4db8e" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentCTAAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_crl_EquityMethodInvestmentCTAAdjustment_5e221bd7-e6ff-419d-bda7-d1df12f4db8e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_eb2ae5b4-9044-4171-a4d6-d660f585b414" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestments"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_85560fb2-3f98-43bf-995c-5cc9cfbe86bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_5da01f91-457a-4ff8-8b10-879a9c25a1ab" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_85560fb2-3f98-43bf-995c-5cc9cfbe86bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_8ecfda2d-1987-478a-8793-bf324d979147" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_85560fb2-3f98-43bf-995c-5cc9cfbe86bc" xlink:to="loc_us-gaap_InvestmentTypeAxis_8ecfda2d-1987-478a-8793-bf324d979147" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_8ecfda2d-1987-478a-8793-bf324d979147_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_8ecfda2d-1987-478a-8793-bf324d979147" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_8ecfda2d-1987-478a-8793-bf324d979147_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_fc5cdfac-9971-4abd-b275-b3ecb8fdc5a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_8ecfda2d-1987-478a-8793-bf324d979147" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_fc5cdfac-9971-4abd-b275-b3ecb8fdc5a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_StrategicInvestmentsMember_8f906732-e70f-4324-8916-9d28551cab38" xlink:href="crl-20221231.xsd#crl_StrategicInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_fc5cdfac-9971-4abd-b275-b3ecb8fdc5a2" xlink:to="loc_crl_StrategicInvestmentsMember_8f906732-e70f-4324-8916-9d28551cab38" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSAdditionalInformationDetails" xlink:type="extended" id="ie46c9e3ceea04bf5adbcb06b3ebbe66f_VENTURECAPITALANDSTRATEGICEQUITYINVESTMENTSAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_ef5df899-e8bb-48df-a225-60093720140b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_ef5df899-e8bb-48df-a225-60093720140b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_7c42f6dc-1c9b-4010-ab62-2d80cdd54c81" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_7c42f6dc-1c9b-4010-ab62-2d80cdd54c81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentContingentLiability_1491962a-e2de-4b7d-9a63-7760c79cc9be" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentContingentLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:to="loc_crl_EquityMethodInvestmentContingentLiability_1491962a-e2de-4b7d-9a63-7760c79cc9be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_7be7c2ac-1740-4c45-8370-d414e15134ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:to="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_7be7c2ac-1740-4c45-8370-d414e15134ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_751f9649-2b57-4c9b-8542-cf6deb32b3f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_ad6930c4-49d4-4a35-8d9e-3f4dbf8b6bcd" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_751f9649-2b57-4c9b-8542-cf6deb32b3f7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_cfe65ae3-b96a-4579-97d6-e12c698522c4" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_751f9649-2b57-4c9b-8542-cf6deb32b3f7" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_cfe65ae3-b96a-4579-97d6-e12c698522c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_cfe65ae3-b96a-4579-97d6-e12c698522c4_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_cfe65ae3-b96a-4579-97d6-e12c698522c4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_cfe65ae3-b96a-4579-97d6-e12c698522c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_be9c8789-8d86-470a-b3b6-a2e1164af206" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_cfe65ae3-b96a-4579-97d6-e12c698522c4" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_be9c8789-8d86-470a-b3b6-a2e1164af206" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DSASupplierMember_8ca14cef-4089-453e-800c-bb91a88b5641" xlink:href="crl-20221231.xsd#crl_DSASupplierMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_be9c8789-8d86-470a-b3b6-a2e1164af206" xlink:to="loc_crl_DSASupplierMember_8ca14cef-4089-453e-800c-bb91a88b5641" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_2de3ad4a-41bb-4b5b-a979-970b35a2274f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_751f9649-2b57-4c9b-8542-cf6deb32b3f7" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_2de3ad4a-41bb-4b5b-a979-970b35a2274f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2de3ad4a-41bb-4b5b-a979-970b35a2274f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_2de3ad4a-41bb-4b5b-a979-970b35a2274f" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2de3ad4a-41bb-4b5b-a979-970b35a2274f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0017c45c-44d0-4cb2-90b3-b42860087c5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_2de3ad4a-41bb-4b5b-a979-970b35a2274f" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0017c45c-44d0-4cb2-90b3-b42860087c5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillMember_541867d5-8944-48b9-bed0-b16b829f8e19" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0017c45c-44d0-4cb2-90b3-b42860087c5e" xlink:to="loc_us-gaap_GoodwillMember_541867d5-8944-48b9-bed0-b16b829f8e19" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMember_36463daa-4b36-4350-81fb-1ff6f8478a37" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0017c45c-44d0-4cb2-90b3-b42860087c5e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMember_36463daa-4b36-4350-81fb-1ff6f8478a37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_ba297191-be79-4de8-8032-8a47f6b89ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_751f9649-2b57-4c9b-8542-cf6deb32b3f7" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_ba297191-be79-4de8-8032-8a47f6b89ec0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_ba297191-be79-4de8-8032-8a47f6b89ec0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_ba297191-be79-4de8-8032-8a47f6b89ec0" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_ba297191-be79-4de8-8032-8a47f6b89ec0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_30039ac2-8479-491d-b562-1755ca0c3756" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_ba297191-be79-4de8-8032-8a47f6b89ec0" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_30039ac2-8479-491d-b562-1755ca0c3756" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DeferredTaxLiabilityMember_cc3596d1-d72d-4b79-ba46-ae028ffba399" xlink:href="crl-20221231.xsd#crl_DeferredTaxLiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_30039ac2-8479-491d-b562-1755ca0c3756" xlink:to="loc_crl_DeferredTaxLiabilityMember_cc3596d1-d72d-4b79-ba46-ae028ffba399" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/FAIRVALUEAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#FAIRVALUEAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/FAIRVALUEAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails" xlink:type="extended" id="i6abe59a939cc4eef9451ee18602596f1_FAIRVALUEAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_18e4ddc0-fea8-42a8-9ca7-8d678b724e6f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_AssetsCurrentAbstract_18e4ddc0-fea8-42a8-9ca7-8d678b724e6f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7f87d627-3776-4eb9-87b8-69624f25425f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_18e4ddc0-fea8-42a8-9ca7-8d678b724e6f" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_7f87d627-3776-4eb9-87b8-69624f25425f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsAbstract_a128f44f-5ea8-4d39-a61e-9f64ff460e24" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_OtherAssetsAbstract_a128f44f-5ea8-4d39-a61e-9f64ff460e24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashSurrenderValueFairValueDisclosure_faf2696c-554f-45da-a117-d95a4e93f7dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashSurrenderValueFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherAssetsAbstract_a128f44f-5ea8-4d39-a61e-9f64ff460e24" xlink:to="loc_us-gaap_CashSurrenderValueFairValueDisclosure_faf2696c-554f-45da-a117-d95a4e93f7dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_a9461898-e39e-497b-9119-1f7643d74297" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_a9461898-e39e-497b-9119-1f7643d74297" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_ac76c500-5d54-422e-a4f9-c18ac8bdd164" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_ac76c500-5d54-422e-a4f9-c18ac8bdd164" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_d1f6591a-7591-4081-a6c3-e1634b79944b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ac76c500-5d54-422e-a4f9-c18ac8bdd164" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityCurrent_d1f6591a-7591-4081-a6c3-e1634b79944b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract_864b7006-070d-46b4-9c8c-6179d09b3e31" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_LiabilitiesNoncurrentAbstract_864b7006-070d-46b4-9c8c-6179d09b3e31" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_09c9edd5-f9c2-4d3d-984e-d7bec804162b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_864b7006-070d-46b4-9c8c-6179d09b3e31" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_09c9edd5-f9c2-4d3d-984e-d7bec804162b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_7266786f-b700-4390-808c-e39545e9c7df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_864b7006-070d-46b4-9c8c-6179d09b3e31" xlink:to="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_7266786f-b700-4390-808c-e39545e9c7df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_01cd7206-d270-4b30-a093-76570e54b31b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract_864b7006-070d-46b4-9c8c-6179d09b3e31" xlink:to="loc_us-gaap_DerivativeLiabilities_01cd7206-d270-4b30-a093-76570e54b31b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_72c8d660-878b-4a8b-97c2-2dfb976e16c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_72c8d660-878b-4a8b-97c2-2dfb976e16c8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3d72e14a-5c63-4bf8-b661-c4f9e3ee70b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_267018de-ae7e-4683-beb5-4bad14d811d5" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3d72e14a-5c63-4bf8-b661-c4f9e3ee70b1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3d72e14a-5c63-4bf8-b661-c4f9e3ee70b1" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a185f13e-800b-4dc2-aca5-6a08ab4e03a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_beb6ac6a-a503-4f3f-a555-a63ddf37f1a2" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a185f13e-800b-4dc2-aca5-6a08ab4e03a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_785e8672-faf9-4676-ba70-2227707e3f53" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a185f13e-800b-4dc2-aca5-6a08ab4e03a0" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_785e8672-faf9-4676-ba70-2227707e3f53" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_c65280a6-7384-4ccb-8431-2d0009339d43" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a185f13e-800b-4dc2-aca5-6a08ab4e03a0" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_c65280a6-7384-4ccb-8431-2d0009339d43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_50f872dc-a39f-4206-8e8a-b9a5709ad7e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a185f13e-800b-4dc2-aca5-6a08ab4e03a0" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_50f872dc-a39f-4206-8e8a-b9a5709ad7e7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/FAIRVALUERollforwardofContingentConsiderationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#FAIRVALUERollforwardofContingentConsiderationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/FAIRVALUERollforwardofContingentConsiderationDetails" xlink:type="extended" id="ic49b606321de442fb4aead7f0b57b9c8_FAIRVALUERollforwardofContingentConsiderationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_83d8def9-7c28-40c0-9014-39873dcb0d0d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_83d8def9-7c28-40c0-9014-39873dcb0d0d" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_8c31362b-cfc8-42f2-ac1c-f9ac9a29e1bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_8c31362b-cfc8-42f2-ac1c-f9ac9a29e1bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases_1d7ac0b4-bb9b-458d-bc5d-422f1c3cef8b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases_1d7ac0b4-bb9b-458d-bc5d-422f1c3cef8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_f2bc9ef1-3a21-4727-b518-9b49edcf67fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_f2bc9ef1-3a21-4727-b518-9b49edcf67fb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract_8bb6ef8d-89ad-4716-a5c2-ac38e894bada" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_59f5453b-97ae-47f7-af03-eff86b353656" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract_8bb6ef8d-89ad-4716-a5c2-ac38e894bada" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_af5c5628-644f-43f2-8fc7-9e555ba7210c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract_8bb6ef8d-89ad-4716-a5c2-ac38e894bada" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_af5c5628-644f-43f2-8fc7-9e555ba7210c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisLiabilityChangeInPreviouslyRecordedAdjustment_df76c06f-7046-42aa-b896-beb42fa659be" xlink:href="crl-20221231.xsd#crl_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisLiabilityChangeInPreviouslyRecordedAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract_8bb6ef8d-89ad-4716-a5c2-ac38e894bada" xlink:to="loc_crl_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisLiabilityChangeInPreviouslyRecordedAdjustment_df76c06f-7046-42aa-b896-beb42fa659be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_b2e18f4f-8953-4237-8ce8-e97b328549a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_911893ee-258c-4289-bc92-87c776059e92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_83d8def9-7c28-40c0-9014-39873dcb0d0d" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_911893ee-258c-4289-bc92-87c776059e92" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_d9e781c7-a51f-4ae5-a772-edfeee3f8b98" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_911893ee-258c-4289-bc92-87c776059e92" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_d9e781c7-a51f-4ae5-a772-edfeee3f8b98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d9e781c7-a51f-4ae5-a772-edfeee3f8b98_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_d9e781c7-a51f-4ae5-a772-edfeee3f8b98" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_d9e781c7-a51f-4ae5-a772-edfeee3f8b98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3ff20fb8-d830-4855-920d-1f847a83b43e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_d9e781c7-a51f-4ae5-a772-edfeee3f8b98" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3ff20fb8-d830-4855-920d-1f847a83b43e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ContingentConsiderationMember_51ee7933-9b34-4f0c-b65b-ef81047006fa" xlink:href="crl-20221231.xsd#crl_ContingentConsiderationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_3ff20fb8-d830-4855-920d-1f847a83b43e" xlink:to="loc_crl_ContingentConsiderationMember_51ee7933-9b34-4f0c-b65b-ef81047006fa" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/FAIRVALUENarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#FAIRVALUENarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/FAIRVALUENarrativeDetails" xlink:type="extended" id="i53b84ff0112b4d8db09de2ab0f7e6ad7_FAIRVALUENarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_9ed7c325-d1c4-44f7-8114-9c20bd60defa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_9ed7c325-d1c4-44f7-8114-9c20bd60defa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_FairValueMeasurementWithUnobservableInputsReconciliationWeightedAverageProbabilityOfMaximumTarget_57d424b9-9ef7-4752-96b7-def91e613ea4" xlink:href="crl-20221231.xsd#crl_FairValueMeasurementWithUnobservableInputsReconciliationWeightedAverageProbabilityOfMaximumTarget"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_crl_FairValueMeasurementWithUnobservableInputsReconciliationWeightedAverageProbabilityOfMaximumTarget_57d424b9-9ef7-4752-96b7-def91e613ea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_bd9bcd85-124a-45a6-90a0-1dd284bd2a12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_bd9bcd85-124a-45a6-90a0-1dd284bd2a12" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_1da31025-1f78-45bb-ab6b-de00e6c6dcdf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_DerivativeNotionalAmount_1da31025-1f78-45bb-ab6b-de00e6c6dcdf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_0c9bd6a8-1c77-4ea5-a8fd-796640153cc4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_0c9bd6a8-1c77-4ea5-a8fd-796640153cc4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8e20a9a1-f896-4fae-a5ca-74dc6a8f4401" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8e20a9a1-f896-4fae-a5ca-74dc6a8f4401" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_af287af6-8432-4413-bad5-0a677dacfc7a" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c9770703-bace-4cd1-aaf6-1b4943efe132" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_74d4c6a9-26d9-4128-b3e3-368f1c3ec75f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c9770703-bace-4cd1-aaf6-1b4943efe132" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_92127c69-1b5b-44fa-b628-fd2884dacc79" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c9770703-bace-4cd1-aaf6-1b4943efe132" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_92127c69-1b5b-44fa-b628-fd2884dacc79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_53bf19fc-2c38-491e-9db0-dc62fc7ae47f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_53bf19fc-2c38-491e-9db0-dc62fc7ae47f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_53bf19fc-2c38-491e-9db0-dc62fc7ae47f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_53bf19fc-2c38-491e-9db0-dc62fc7ae47f" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_53bf19fc-2c38-491e-9db0-dc62fc7ae47f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_5ed10bdf-feba-429c-8efa-bfdfd873856d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_53bf19fc-2c38-491e-9db0-dc62fc7ae47f" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_5ed10bdf-feba-429c-8efa-bfdfd873856d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ContingentConsiderationMember_debc4208-f517-4548-9463-11c4d3919e02" xlink:href="crl-20221231.xsd#crl_ContingentConsiderationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_5ed10bdf-feba-429c-8efa-bfdfd873856d" xlink:to="loc_crl_ContingentConsiderationMember_debc4208-f517-4548-9463-11c4d3919e02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5e2e772a-2033-4435-93c1-1507d94f31aa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_srt_RangeAxis_5e2e772a-2033-4435-93c1-1507d94f31aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5e2e772a-2033-4435-93c1-1507d94f31aa_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5e2e772a-2033-4435-93c1-1507d94f31aa" xlink:to="loc_srt_RangeMember_5e2e772a-2033-4435-93c1-1507d94f31aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f316d794-8a78-4cd5-9578-0671624bb723" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5e2e772a-2033-4435-93c1-1507d94f31aa" xlink:to="loc_srt_RangeMember_f316d794-8a78-4cd5-9578-0671624bb723" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_12b6d8b1-4064-42ac-828d-6432bbc8c9f0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f316d794-8a78-4cd5-9578-0671624bb723" xlink:to="loc_srt_MaximumMember_12b6d8b1-4064-42ac-828d-6432bbc8c9f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_9f036a06-e301-40d3-bb7f-b36623af26af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_9f036a06-e301-40d3-bb7f-b36623af26af" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_9f036a06-e301-40d3-bb7f-b36623af26af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_9f036a06-e301-40d3-bb7f-b36623af26af" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_9f036a06-e301-40d3-bb7f-b36623af26af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_f41e6c26-1ece-420b-b663-dee66177ce23" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_9f036a06-e301-40d3-bb7f-b36623af26af" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_f41e6c26-1ece-420b-b663-dee66177ce23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputPriceVolatilityMember_e65feda5-a61c-4397-bf29-59a203e5d9b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_f41e6c26-1ece-420b-b663-dee66177ce23" xlink:to="loc_us-gaap_MeasurementInputPriceVolatilityMember_e65feda5-a61c-4397-bf29-59a203e5d9b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_daa0aa8a-98ab-40a8-9fe8-5d6403b025bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_f41e6c26-1ece-420b-b663-dee66177ce23" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_daa0aa8a-98ab-40a8-9fe8-5d6403b025bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_4589a34e-aa5f-46df-9b17-1be9b6fba3ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_4589a34e-aa5f-46df-9b17-1be9b6fba3ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4589a34e-aa5f-46df-9b17-1be9b6fba3ef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4589a34e-aa5f-46df-9b17-1be9b6fba3ef" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4589a34e-aa5f-46df-9b17-1be9b6fba3ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_f6e95952-e807-4725-bf7d-7c67d9ba7969" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4589a34e-aa5f-46df-9b17-1be9b6fba3ef" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_f6e95952-e807-4725-bf7d-7c67d9ba7969" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_e220b2a3-5986-4214-a095-f1df8cc9911c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_f6e95952-e807-4725-bf7d-7c67d9ba7969" xlink:to="loc_us-gaap_LineOfCreditMember_e220b2a3-5986-4214-a095-f1df8cc9911c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_c2982855-437d-49c3-83fe-57c9b6c37fc7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_c2982855-437d-49c3-83fe-57c9b6c37fc7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c2982855-437d-49c3-83fe-57c9b6c37fc7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_c2982855-437d-49c3-83fe-57c9b6c37fc7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c2982855-437d-49c3-83fe-57c9b6c37fc7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_653b6a50-1fab-4595-90d4-658a54560862" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_c2982855-437d-49c3-83fe-57c9b6c37fc7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_653b6a50-1fab-4595-90d4-658a54560862" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_f16efece-c6ea-423e-8986-3bf97c840438" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_653b6a50-1fab-4595-90d4-658a54560862" xlink:to="loc_us-gaap_InterestRateSwapMember_f16efece-c6ea-423e-8986-3bf97c840438" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_004ca451-f287-4a79-a55f-7e249877684f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_dd45213f-597a-4588-91cf-50716cce3f8a" xlink:to="loc_us-gaap_HedgingDesignationAxis_004ca451-f287-4a79-a55f-7e249877684f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_004ca451-f287-4a79-a55f-7e249877684f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_004ca451-f287-4a79-a55f-7e249877684f" xlink:to="loc_us-gaap_HedgingDesignationDomain_004ca451-f287-4a79-a55f-7e249877684f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_2892f35b-dadc-4413-b273-84be2dfd4679" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_004ca451-f287-4a79-a55f-7e249877684f" xlink:to="loc_us-gaap_HedgingDesignationDomain_2892f35b-dadc-4413-b273-84be2dfd4679" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_683171fd-560e-4074-8cd6-3b951b852e77" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_2892f35b-dadc-4413-b273-84be2dfd4679" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_683171fd-560e-4074-8cd6-3b951b852e77" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/FAIRVALUEDebtInstrumentsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#FAIRVALUEDebtInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/FAIRVALUEDebtInstrumentsDetails" xlink:type="extended" id="i0d3f4af2550545ea891cfc36157beebe_FAIRVALUEDebtInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_040967d9-a98e-4210-ab80-84324a9dea58" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_d069e2c3-e13d-4a95-bb60-803f10b41f92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_040967d9-a98e-4210-ab80-84324a9dea58" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_d069e2c3-e13d-4a95-bb60-803f10b41f92" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_863726c8-d53c-4f4d-ba7d-245fbe4e8e80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_040967d9-a98e-4210-ab80-84324a9dea58" xlink:to="loc_us-gaap_DebtInstrumentFairValue_863726c8-d53c-4f4d-ba7d-245fbe4e8e80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_3d54a4ce-94ed-4d13-a55f-f1bfcdec89a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_040967d9-a98e-4210-ab80-84324a9dea58" xlink:to="loc_us-gaap_DebtInstrumentTable_3d54a4ce-94ed-4d13-a55f-f1bfcdec89a4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2d006985-70bc-495a-b148-fbc1cb843c4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3d54a4ce-94ed-4d13-a55f-f1bfcdec89a4" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2d006985-70bc-495a-b148-fbc1cb843c4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2d006985-70bc-495a-b148-fbc1cb843c4c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2d006985-70bc-495a-b148-fbc1cb843c4c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2d006985-70bc-495a-b148-fbc1cb843c4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_210e435a-7163-4786-8e31-3dacf2cef89f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2d006985-70bc-495a-b148-fbc1cb843c4c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_210e435a-7163-4786-8e31-3dacf2cef89f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_547c2123-72a4-44e8-990b-8bbe05aaff9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_210e435a-7163-4786-8e31-3dacf2cef89f" xlink:to="loc_us-gaap_SeniorNotesMember_547c2123-72a4-44e8-990b-8bbe05aaff9f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_eda80b87-990a-4b75-a0f6-a952e3f64fb4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3d54a4ce-94ed-4d13-a55f-f1bfcdec89a4" xlink:to="loc_us-gaap_DebtInstrumentAxis_eda80b87-990a-4b75-a0f6-a952e3f64fb4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_eda80b87-990a-4b75-a0f6-a952e3f64fb4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_eda80b87-990a-4b75-a0f6-a952e3f64fb4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_eda80b87-990a-4b75-a0f6-a952e3f64fb4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_cfd87849-4da9-4522-bfd0-8edb5e97c384" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_eda80b87-990a-4b75-a0f6-a952e3f64fb4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_cfd87849-4da9-4522-bfd0-8edb5e97c384" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2028Member_8b6a0e88-3d5e-446b-b06f-cf7d7392150e" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cfd87849-4da9-4522-bfd0-8edb5e97c384" xlink:to="loc_crl_SeniorNotesDue2028Member_8b6a0e88-3d5e-446b-b06f-cf7d7392150e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2029Member_07506e35-232a-4ae4-9404-38c11942b28e" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cfd87849-4da9-4522-bfd0-8edb5e97c384" xlink:to="loc_crl_SeniorNotesDue2029Member_07506e35-232a-4ae4-9404-38c11942b28e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2031Member_870673c2-8c07-41d9-a543-917d1c3aab1f" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cfd87849-4da9-4522-bfd0-8edb5e97c384" xlink:to="loc_crl_SeniorNotesDue2031Member_870673c2-8c07-41d9-a543-917d1c3aab1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_469c09fa-11f5-42e6-9133-d24545d35278" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_3d54a4ce-94ed-4d13-a55f-f1bfcdec89a4" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_469c09fa-11f5-42e6-9133-d24545d35278" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_469c09fa-11f5-42e6-9133-d24545d35278_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_469c09fa-11f5-42e6-9133-d24545d35278" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_469c09fa-11f5-42e6-9133-d24545d35278_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_18ab220a-adc2-4fe6-99ad-38cec57417f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_469c09fa-11f5-42e6-9133-d24545d35278" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_18ab220a-adc2-4fe6-99ad-38cec57417f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0fd0f646-4592-42c0-aedd-1dce03c61f39" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_18ab220a-adc2-4fe6-99ad-38cec57417f0" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0fd0f646-4592-42c0-aedd-1dce03c61f39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9d8fd7b1-3b7e-40c7-b97f-9ad6a227cf03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0fd0f646-4592-42c0-aedd-1dce03c61f39" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_9d8fd7b1-3b7e-40c7-b97f-9ad6a227cf03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_af04be85-2874-42e9-89bc-85f90c4e10de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_0fd0f646-4592-42c0-aedd-1dce03c61f39" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_af04be85-2874-42e9-89bc-85f90c4e10de" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/GOODWILLANDINTANGIBLEASSETSRollforwardofCompanysGoodwillDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#GOODWILLANDINTANGIBLEASSETSRollforwardofCompanysGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/GOODWILLANDINTANGIBLEASSETSRollforwardofCompanysGoodwillDetails" xlink:type="extended" id="i4d184f4b796f40fab9d0c15461aa8687_GOODWILLANDINTANGIBLEASSETSRollforwardofCompanysGoodwillDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_5f959758-c619-44e8-b60e-ed07aada31e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_5f959758-c619-44e8-b60e-ed07aada31e4" xlink:to="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_097636bf-9d7e-477d-a5e1-39f13d643283" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:to="loc_us-gaap_GoodwillGross_097636bf-9d7e-477d-a5e1-39f13d643283" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_GoodwillAcquiredDuringPeriodNet_77d52fde-ad2f-4d01-bc3a-1939bb769225" xlink:href="crl-20221231.xsd#crl_GoodwillAcquiredDuringPeriodNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:to="loc_crl_GoodwillAcquiredDuringPeriodNet_77d52fde-ad2f-4d01-bc3a-1939bb769225" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_25535a88-c723-479e-b975-253d2dc32494" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:to="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_25535a88-c723-479e-b975-253d2dc32494" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_18f64598-d61f-433a-b8e6-89c5c40abad1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_6a85d807-6c6a-40a1-9673-e7479816c68f" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_18f64598-d61f-433a-b8e6-89c5c40abad1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_0cbdf3f7-b2e5-4723-a079-70d9a7762abf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillGross"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_d362a586-206c-4981-9b73-4f9ec169ff00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_5f959758-c619-44e8-b60e-ed07aada31e4" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_d362a586-206c-4981-9b73-4f9ec169ff00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_50919ead-7e5f-4abd-b60d-d96b3c50f1c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_5f959758-c619-44e8-b60e-ed07aada31e4" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_50919ead-7e5f-4abd-b60d-d96b3c50f1c8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_19f642e6-5f02-483c-be92-8017b2b7f366" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_50919ead-7e5f-4abd-b60d-d96b3c50f1c8" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_19f642e6-5f02-483c-be92-8017b2b7f366" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_19f642e6-5f02-483c-be92-8017b2b7f366_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_19f642e6-5f02-483c-be92-8017b2b7f366" xlink:to="loc_us-gaap_SegmentDomain_19f642e6-5f02-483c-be92-8017b2b7f366_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_beb1ea0f-05b6-42cc-8434-8d13c22c3f84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_19f642e6-5f02-483c-be92-8017b2b7f366" xlink:to="loc_us-gaap_SegmentDomain_beb1ea0f-05b6-42cc-8434-8d13c22c3f84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ResearchModelsAndServicesMember_6533ff80-0f96-42eb-bc21-a188c1ad6cd2" xlink:href="crl-20221231.xsd#crl_ResearchModelsAndServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_beb1ea0f-05b6-42cc-8434-8d13c22c3f84" xlink:to="loc_crl_ResearchModelsAndServicesMember_6533ff80-0f96-42eb-bc21-a188c1ad6cd2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DiscoveryandSafetyAssessmentMember_57b1d92b-a41d-4a0e-95f2-8e6e80a12f7d" xlink:href="crl-20221231.xsd#crl_DiscoveryandSafetyAssessmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_beb1ea0f-05b6-42cc-8434-8d13c22c3f84" xlink:to="loc_crl_DiscoveryandSafetyAssessmentMember_57b1d92b-a41d-4a0e-95f2-8e6e80a12f7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ManufacturingSupportMember_d6c9bde6-f75c-489e-a813-db39079bb144" xlink:href="crl-20221231.xsd#crl_ManufacturingSupportMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_beb1ea0f-05b6-42cc-8434-8d13c22c3f84" xlink:to="loc_crl_ManufacturingSupportMember_d6c9bde6-f75c-489e-a813-db39079bb144" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsNetbyMajorClassDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#GOODWILLANDINTANGIBLEASSETSIntangibleAssetsNetbyMajorClassDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsNetbyMajorClassDetails" xlink:type="extended" id="i7e38db916d0541a0a128d59d8dfce84e_GOODWILLANDINTANGIBLEASSETSIntangibleAssetsNetbyMajorClassDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e7ecf7c1-972d-4833-9857-f19899bff595" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_3ed16378-fd25-4102-ac0b-7b9ed15a669a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e7ecf7c1-972d-4833-9857-f19899bff595" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_3ed16378-fd25-4102-ac0b-7b9ed15a669a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_3341f78c-fc5f-41f7-af13-13de49d0bb60" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e7ecf7c1-972d-4833-9857-f19899bff595" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_3341f78c-fc5f-41f7-af13-13de49d0bb60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_70cac435-4898-4855-bcaa-1d952ef21b99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e7ecf7c1-972d-4833-9857-f19899bff595" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_70cac435-4898-4855-bcaa-1d952ef21b99" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_184c5552-f886-46f7-925f-5f07b86cde8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_e7ecf7c1-972d-4833-9857-f19899bff595" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_184c5552-f886-46f7-925f-5f07b86cde8c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2184048c-4fb6-4600-8fc6-fdc296e2bed3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_184c5552-f886-46f7-925f-5f07b86cde8c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2184048c-4fb6-4600-8fc6-fdc296e2bed3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2184048c-4fb6-4600-8fc6-fdc296e2bed3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2184048c-4fb6-4600-8fc6-fdc296e2bed3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2184048c-4fb6-4600-8fc6-fdc296e2bed3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_2184048c-4fb6-4600-8fc6-fdc296e2bed3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrderOrProductionBacklogMember_5e548574-5c1e-4e77-854b-56ed36fef27f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrderOrProductionBacklogMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:to="loc_us-gaap_OrderOrProductionBacklogMember_5e548574-5c1e-4e77-854b-56ed36fef27f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_7a59916e-9636-4129-be02-8f6511b396e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TechnologyBasedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:to="loc_us-gaap_TechnologyBasedIntangibleAssetsMember_7a59916e-9636-4129-be02-8f6511b396e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_7b9a677a-6f80-407b-a1c8-38546fbe306c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_7b9a677a-6f80-407b-a1c8-38546fbe306c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_654406f2-795b-4542-8745-a8fd5b43c236" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_654406f2-795b-4542-8745-a8fd5b43c236" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_86afc57f-ee92-4ad5-974d-0309d143eb3f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_076872da-a612-493c-86c4-8e2ade15bc41" xlink:to="loc_us-gaap_CustomerRelationshipsMember_86afc57f-ee92-4ad5-974d-0309d143eb3f" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSLongtermDebtNetDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DEBTANDOTHERFINANCINGARRANGEMENTSLongtermDebtNetDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSLongtermDebtNetDetails" xlink:type="extended" id="i23ecd4067fab489f8127f06ceed21691_DEBTANDOTHERFINANCINGARRANGEMENTSLongtermDebtNetDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_45b68d32-c24a-40c6-adf5-306059bede30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_45b68d32-c24a-40c6-adf5-306059bede30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_e19c6977-9e41-4b95-99c1-563c555649f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_e19c6977-9e41-4b95-99c1-563c555649f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiability_021f1f65-4a4d-41fa-8d04-47d3020e2197" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_FinanceLeaseLiability_021f1f65-4a4d-41fa-8d04-47d3020e2197" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_LongtermDebtGrossAndLeaseObligation_3f96db4a-5f97-44fb-87ea-b98b4dd9526b" xlink:href="crl-20221231.xsd#crl_LongtermDebtGrossAndLeaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_crl_LongtermDebtGrossAndLeaseObligation_3f96db4a-5f97-44fb-87ea-b98b4dd9526b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_ee80a725-6a90-4fd7-b89d-be218bb69928" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_LongTermDebtCurrent_ee80a725-6a90-4fd7-b89d-be218bb69928" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_f833c821-d225-429a-ba31-c192187064ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_f833c821-d225-429a-ba31-c192187064ef" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_0a4b1a52-69da-4427-9a84-232cac905bcc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_0a4b1a52-69da-4427-9a84-232cac905bcc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_LongTermDebtAndLeaseObligationNetOfCurrentPortion_278042c2-1a7d-40ff-85fb-8c912c542c75" xlink:href="crl-20221231.xsd#crl_LongTermDebtAndLeaseObligationNetOfCurrentPortion"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_crl_LongTermDebtAndLeaseObligationNetOfCurrentPortion_278042c2-1a7d-40ff-85fb-8c912c542c75" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_87ec8190-645a-4068-a7ed-f63f1372ae24" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_87ec8190-645a-4068-a7ed-f63f1372ae24" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_3ab197e5-1377-4105-8fe6-f161e74da864" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_3ab197e5-1377-4105-8fe6-f161e74da864" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_783c33bc-fc9c-4e92-a2c7-f9fb47c9c96b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4f1ed673-b5b7-447d-a14d-c2ff44fa67d9" xlink:to="loc_us-gaap_DebtInstrumentTable_783c33bc-fc9c-4e92-a2c7-f9fb47c9c96b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_769f6a34-659d-47be-8246-50c85bc0f5dd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_783c33bc-fc9c-4e92-a2c7-f9fb47c9c96b" xlink:to="loc_us-gaap_DebtInstrumentAxis_769f6a34-659d-47be-8246-50c85bc0f5dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_769f6a34-659d-47be-8246-50c85bc0f5dd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_769f6a34-659d-47be-8246-50c85bc0f5dd" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_769f6a34-659d-47be-8246-50c85bc0f5dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0fd0f8d1-e891-4902-8a85-4f65b3690db3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_769f6a34-659d-47be-8246-50c85bc0f5dd" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0fd0f8d1-e891-4902-8a85-4f65b3690db3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2028Member_0167661e-c685-4901-ab2a-55a95cb7edad" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0fd0f8d1-e891-4902-8a85-4f65b3690db3" xlink:to="loc_crl_SeniorNotesDue2028Member_0167661e-c685-4901-ab2a-55a95cb7edad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2029Member_3776fa03-f228-47d2-98e3-db388ad7a103" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0fd0f8d1-e891-4902-8a85-4f65b3690db3" xlink:to="loc_crl_SeniorNotesDue2029Member_3776fa03-f228-47d2-98e3-db388ad7a103" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2031Member_6b314321-0d97-4ebc-8a91-450f510d7473" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0fd0f8d1-e891-4902-8a85-4f65b3690db3" xlink:to="loc_crl_SeniorNotesDue2031Member_6b314321-0d97-4ebc-8a91-450f510d7473" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_00f99a7a-44cb-4b56-885f-166fd6425241" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_783c33bc-fc9c-4e92-a2c7-f9fb47c9c96b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_00f99a7a-44cb-4b56-885f-166fd6425241" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_00f99a7a-44cb-4b56-885f-166fd6425241_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_00f99a7a-44cb-4b56-885f-166fd6425241" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_00f99a7a-44cb-4b56-885f-166fd6425241_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4daa33fa-616d-4e13-834b-0cfe5c7e4257" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_00f99a7a-44cb-4b56-885f-166fd6425241" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4daa33fa-616d-4e13-834b-0cfe5c7e4257" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_4d0c3e86-fe6b-407e-a78a-86ced43a66e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_4daa33fa-616d-4e13-834b-0cfe5c7e4257" xlink:to="loc_us-gaap_LineOfCreditMember_4d0c3e86-fe6b-407e-a78a-86ced43a66e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_ccffea27-70c5-400c-b8e4-803f73f6afff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_4daa33fa-616d-4e13-834b-0cfe5c7e4257" xlink:to="loc_us-gaap_SeniorNotesMember_ccffea27-70c5-400c-b8e4-803f73f6afff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherLongTermDebtMember_bdb125bd-da47-473c-9a14-53454588d48c" xlink:href="crl-20221231.xsd#crl_OtherLongTermDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_4daa33fa-616d-4e13-834b-0cfe5c7e4257" xlink:to="loc_crl_OtherLongTermDebtMember_bdb125bd-da47-473c-9a14-53454588d48c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DEBTANDOTHERFINANCINGARRANGEMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSNarrativeDetails" xlink:type="extended" id="ic2f832dddd4e416f94848a7824deaa6c_DEBTANDOTHERFINANCINGARRANGEMENTSNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtWeightedAverageInterestRate_ce4d9e69-71a7-4b0d-8d63-2a3ca1ce30f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DebtWeightedAverageInterestRate_ce4d9e69-71a7-4b0d-8d63-2a3ca1ce30f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_ca7ce3ba-1489-4dfc-b7b5-6f8bda3ed74e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_ca7ce3ba-1489-4dfc-b7b5-6f8bda3ed74e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_8db0ff1f-7e0b-4982-9f40-6f5780577657" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_8db0ff1f-7e0b-4982-9f40-6f5780577657" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_PaymentsForAccruedInterest_1902da43-ed4c-4ad9-b25a-7311c2680fe3" xlink:href="crl-20221231.xsd#crl_PaymentsForAccruedInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_crl_PaymentsForAccruedInterest_1902da43-ed4c-4ad9-b25a-7311c2680fe3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_8e91b74d-e8ef-4947-ae30-534899849a2d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_8e91b74d-e8ef-4947-ae30-534899849a2d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_3488ee36-1998-4a57-bd0a-141f39effb0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_3488ee36-1998-4a57-bd0a-141f39effb0b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_72749af0-8315-43b5-832a-ca4f66017c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_72749af0-8315-43b5-832a-ca4f66017c4b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DebtInstrumentCovenantEBITDALessCapitalExpenditurestoConsolidatedCashInterestExpenseRatioMinimum_aa44eae6-0a83-451e-857f-9fdc7aa9b383" xlink:href="crl-20221231.xsd#crl_DebtInstrumentCovenantEBITDALessCapitalExpenditurestoConsolidatedCashInterestExpenseRatioMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_crl_DebtInstrumentCovenantEBITDALessCapitalExpenditurestoConsolidatedCashInterestExpenseRatioMinimum_aa44eae6-0a83-451e-857f-9fdc7aa9b383" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DebtInstrumentCovenantConsolidatedIndebtednesstoConsolidatedEBITDAMaximum_060050cf-62a6-4879-96a6-7e41a4aef5d8" xlink:href="crl-20221231.xsd#crl_DebtInstrumentCovenantConsolidatedIndebtednesstoConsolidatedEBITDAMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_crl_DebtInstrumentCovenantConsolidatedIndebtednesstoConsolidatedEBITDAMaximum_060050cf-62a6-4879-96a6-7e41a4aef5d8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_203d93ca-b669-46bd-9005-bca5dfa0ac0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_203d93ca-b669-46bd-9005-bca5dfa0ac0f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_44de9075-1133-4f6c-8ff8-5dfdda859735" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_44de9075-1133-4f6c-8ff8-5dfdda859735" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_e9001985-51c7-4149-a52e-d21b8e940a7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DerivativeNotionalAmount_e9001985-51c7-4149-a52e-d21b8e940a7b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_dad44acb-200f-4091-ace0-4d16651ed951" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_dad44acb-200f-4091-ace0-4d16651ed951" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_c366b75a-479d-463a-b3d2-3ecf95635fb7" xlink:to="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_c062d199-f777-4015-a718-4b455d595c71" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_c062d199-f777-4015-a718-4b455d595c71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c062d199-f777-4015-a718-4b455d595c71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c062d199-f777-4015-a718-4b455d595c71" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c062d199-f777-4015-a718-4b455d595c71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2f179d7c-a536-49e6-8bec-2c8d3d5bfaae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c062d199-f777-4015-a718-4b455d595c71" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2f179d7c-a536-49e6-8bec-2c8d3d5bfaae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_a4e06bdc-49ce-4f70-a7ca-6dd5631273c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_2f179d7c-a536-49e6-8bec-2c8d3d5bfaae" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_a4e06bdc-49ce-4f70-a7ca-6dd5631273c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_a9dffdbb-0741-4787-a3e2-da5ceed2a140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_2f179d7c-a536-49e6-8bec-2c8d3d5bfaae" xlink:to="loc_us-gaap_InterestExpenseMember_a9dffdbb-0741-4787-a3e2-da5ceed2a140" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_217809ee-a8bc-4cec-b385-9c470cfa68fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_217809ee-a8bc-4cec-b385-9c470cfa68fa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_217809ee-a8bc-4cec-b385-9c470cfa68fa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_217809ee-a8bc-4cec-b385-9c470cfa68fa" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_217809ee-a8bc-4cec-b385-9c470cfa68fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ca7a7572-8ab2-487a-8df0-38230d9b30cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_217809ee-a8bc-4cec-b385-9c470cfa68fa" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ca7a7572-8ab2-487a-8df0-38230d9b30cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_2c76bb32-a09c-47e7-bf8b-83fdb084b046" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ca7a7572-8ab2-487a-8df0-38230d9b30cb" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_2c76bb32-a09c-47e7-bf8b-83fdb084b046" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_174edbdb-7a03-41cf-8d45-a3ee13927ab8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_174edbdb-7a03-41cf-8d45-a3ee13927ab8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_174edbdb-7a03-41cf-8d45-a3ee13927ab8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_174edbdb-7a03-41cf-8d45-a3ee13927ab8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_174edbdb-7a03-41cf-8d45-a3ee13927ab8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2ab88496-05c5-41d4-ae19-66f4e746694f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_174edbdb-7a03-41cf-8d45-a3ee13927ab8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2ab88496-05c5-41d4-ae19-66f4e746694f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_4618ae9a-de50-466c-8651-a4a5e8b84dde" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2ab88496-05c5-41d4-ae19-66f4e746694f" xlink:to="loc_us-gaap_SeniorNotesMember_4618ae9a-de50-466c-8651-a4a5e8b84dde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember_9ae50922-b455-4536-b348-0c7ce296b528" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MediumTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2ab88496-05c5-41d4-ae19-66f4e746694f" xlink:to="loc_us-gaap_MediumTermNotesMember_9ae50922-b455-4536-b348-0c7ce296b528" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_ccbf5bb3-7046-4081-840a-b0996e2c5d6d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_CreditFacilityAxis_ccbf5bb3-7046-4081-840a-b0996e2c5d6d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_ccbf5bb3-7046-4081-840a-b0996e2c5d6d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_ccbf5bb3-7046-4081-840a-b0996e2c5d6d" xlink:to="loc_us-gaap_CreditFacilityDomain_ccbf5bb3-7046-4081-840a-b0996e2c5d6d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_e8842338-229a-4715-9089-affaf6b1e6e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_ccbf5bb3-7046-4081-840a-b0996e2c5d6d" xlink:to="loc_us-gaap_CreditFacilityDomain_e8842338-229a-4715-9089-affaf6b1e6e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_96034ea9-85e1-4d46-b212-54a5278720c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e8842338-229a-4715-9089-affaf6b1e6e5" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_96034ea9-85e1-4d46-b212-54a5278720c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4136398f-e2a0-49cb-9a76-5eb9cc5a000c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_DebtInstrumentAxis_4136398f-e2a0-49cb-9a76-5eb9cc5a000c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4136398f-e2a0-49cb-9a76-5eb9cc5a000c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4136398f-e2a0-49cb-9a76-5eb9cc5a000c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4136398f-e2a0-49cb-9a76-5eb9cc5a000c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4136398f-e2a0-49cb-9a76-5eb9cc5a000c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2028Member_4fdf3181-c811-4d53-a907-beb54639d3f5" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_SeniorNotesDue2028Member_4fdf3181-c811-4d53-a907-beb54639d3f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2029Member_d345ca62-209c-48e2-8b7d-67497909653c" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_SeniorNotesDue2029Member_d345ca62-209c-48e2-8b7d-67497909653c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2031Member_ffc429c7-c8d5-4fbf-8871-804ebc5deffe" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_SeniorNotesDue2031Member_ffc429c7-c8d5-4fbf-8871-804ebc5deffe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2026Member_969b9af4-62c9-406b-af06-362ecb7065ba" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_SeniorNotesDue2026Member_969b9af4-62c9-406b-af06-362ecb7065ba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ThreeBillionCreditFacilityMember_4e87dde3-309c-4daf-85e0-e2124b4f827e" xlink:href="crl-20221231.xsd#crl_ThreeBillionCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_ThreeBillionCreditFacilityMember_4e87dde3-309c-4daf-85e0-e2124b4f827e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_0ae615ae-04f7-4238-bf58-003ad63a205d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_us-gaap_LetterOfCreditMember_0ae615ae-04f7-4238-bf58-003ad63a205d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeniorNotesDue2029And2031Member_0d559a1f-7a36-410c-a0f5-394472d54219" xlink:href="crl-20221231.xsd#crl_SeniorNotesDue2029And2031Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_6b15eef1-5be5-4a22-87bc-3ea5121254f6" xlink:to="loc_crl_SeniorNotesDue2029And2031Member_0d559a1f-7a36-410c-a0f5-394472d54219" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_6c43779b-b145-4546-bdd7-52fbb1299d65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_us-gaap_VariableRateAxis_6c43779b-b145-4546-bdd7-52fbb1299d65" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_6c43779b-b145-4546-bdd7-52fbb1299d65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_6c43779b-b145-4546-bdd7-52fbb1299d65" xlink:to="loc_us-gaap_VariableRateDomain_6c43779b-b145-4546-bdd7-52fbb1299d65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_858c40e8-f453-49ea-9450-366c77214a2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_6c43779b-b145-4546-bdd7-52fbb1299d65" xlink:to="loc_us-gaap_VariableRateDomain_858c40e8-f453-49ea-9450-366c77214a2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsEffectiveSwapRateMember_ec8d2e1b-3b7b-4399-a459-53b648ae1e48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FederalFundsEffectiveSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_858c40e8-f453-49ea-9450-366c77214a2f" xlink:to="loc_us-gaap_FederalFundsEffectiveSwapRateMember_ec8d2e1b-3b7b-4399-a459-53b648ae1e48" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_b39c3202-fd47-4de6-a2e6-0ac166dccad2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_858c40e8-f453-49ea-9450-366c77214a2f" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_b39c3202-fd47-4de6-a2e6-0ac166dccad2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_8e0790d7-1c55-482a-969b-6cd6d68aa844" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d0a6f97e-820d-4fcb-bcff-09d3ccf331e8" xlink:to="loc_srt_RangeAxis_8e0790d7-1c55-482a-969b-6cd6d68aa844" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8e0790d7-1c55-482a-969b-6cd6d68aa844_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8e0790d7-1c55-482a-969b-6cd6d68aa844" xlink:to="loc_srt_RangeMember_8e0790d7-1c55-482a-969b-6cd6d68aa844_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0d56b407-dc08-4024-86a0-673db1391cce" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8e0790d7-1c55-482a-969b-6cd6d68aa844" xlink:to="loc_srt_RangeMember_0d56b407-dc08-4024-86a0-673db1391cce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_dc6c647c-0704-4393-8fe4-da4394d334fc" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0d56b407-dc08-4024-86a0-673db1391cce" xlink:to="loc_srt_MaximumMember_dc6c647c-0704-4393-8fe4-da4394d334fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_27f2110d-d1e9-464a-9aae-5dfdd176d6e6" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0d56b407-dc08-4024-86a0-673db1391cce" xlink:to="loc_srt_MinimumMember_27f2110d-d1e9-464a-9aae-5dfdd176d6e6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSCrossCurrencyLoansDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#DEBTANDOTHERFINANCINGARRANGEMENTSCrossCurrencyLoansDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/DEBTANDOTHERFINANCINGARRANGEMENTSCrossCurrencyLoansDetails" xlink:type="extended" id="if9b65df4640746299b8c398d1ac30e8d_DEBTANDOTHERFINANCINGARRANGEMENTSCrossCurrencyLoansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_2341d286-0e63-45d0-b2fb-337ea3582cd0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_cce9d2b3-0a88-4723-afd1-b9cda81d0333" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_2341d286-0e63-45d0-b2fb-337ea3582cd0" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_cce9d2b3-0a88-4723-afd1-b9cda81d0333" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_ede0c6da-2d74-4bff-92e0-4cdc4d4f09c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_2341d286-0e63-45d0-b2fb-337ea3582cd0" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_ede0c6da-2d74-4bff-92e0-4cdc4d4f09c3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_7a98de8b-8c2c-4069-a095-f8b498b950db" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_ede0c6da-2d74-4bff-92e0-4cdc4d4f09c3" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_7a98de8b-8c2c-4069-a095-f8b498b950db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7a98de8b-8c2c-4069-a095-f8b498b950db_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7a98de8b-8c2c-4069-a095-f8b498b950db" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7a98de8b-8c2c-4069-a095-f8b498b950db_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_2d1a2130-c650-4f92-8c94-bcccb0e611eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_7a98de8b-8c2c-4069-a095-f8b498b950db" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_2d1a2130-c650-4f92-8c94-bcccb0e611eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_253fc929-df5c-48bc-b2fa-bd11eee3e1fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2d1a2130-c650-4f92-8c94-bcccb0e611eb" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_253fc929-df5c-48bc-b2fa-bd11eee3e1fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_e4a31a02-8e31-42f5-83be-74d966d6c20e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_ede0c6da-2d74-4bff-92e0-4cdc4d4f09c3" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_e4a31a02-8e31-42f5-83be-74d966d6c20e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_e4a31a02-8e31-42f5-83be-74d966d6c20e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e4a31a02-8e31-42f5-83be-74d966d6c20e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_e4a31a02-8e31-42f5-83be-74d966d6c20e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_287e022b-7b34-43ff-9003-b5ced7a847b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e4a31a02-8e31-42f5-83be-74d966d6c20e" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_287e022b-7b34-43ff-9003-b5ced7a847b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_b922468d-97dd-4a7b-9bf9-93c8bc7926d7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_287e022b-7b34-43ff-9003-b5ced7a847b5" xlink:to="loc_us-gaap_InterestExpenseMember_b922468d-97dd-4a7b-9bf9-93c8bc7926d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_5d3f5488-8a97-4baa-b9ac-66528bb9be93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_287e022b-7b34-43ff-9003-b5ced7a847b5" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_5d3f5488-8a97-4baa-b9ac-66528bb9be93" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EQUITYANDNONCONTROLLINGINTERESTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSNarrativeDetails" xlink:type="extended" id="ice962c3f444542f38dc13a312fd94a53_EQUITYANDNONCONTROLLINGINTERESTSNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:href="crl-20221231.xsd#crl_StockRepurchasesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_3d1893c0-3caa-43a6-b94b-953fb75ed928" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_3d1893c0-3caa-43a6-b94b-953fb75ed928" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_115dd693-5af8-4406-9cc7-c8a7660521d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_115dd693-5af8-4406-9cc7-c8a7660521d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_da7a9079-4892-4227-85db-fe0e3b74a32f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_da7a9079-4892-4227-85db-fe0e3b74a32f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_4226f915-1f87-4f24-83a7-dea785bf1616" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_4226f915-1f87-4f24-83a7-dea785bf1616" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_e5eeb0ef-60c7-4045-ae7a-27fa37d9821e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_e5eeb0ef-60c7-4045-ae7a-27fa37d9821e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesRetired_73ef2c52-752d-485e-8203-94f823010450" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockSharesRetired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_us-gaap_TreasuryStockSharesRetired_73ef2c52-752d-485e-8203-94f823010450" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ScheduleOfStockRepurchasesTable_d1fb8966-3454-4e43-9fd5-93cd9884f2e4" xlink:href="crl-20221231.xsd#crl_ScheduleOfStockRepurchasesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_crl_StockRepurchasesLineItems_a883ae2c-c0e6-45d2-948f-ba20f6e9a740" xlink:to="loc_crl_ScheduleOfStockRepurchasesTable_d1fb8966-3454-4e43-9fd5-93cd9884f2e4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_crl_ScheduleOfStockRepurchasesTable_d1fb8966-3454-4e43-9fd5-93cd9884f2e4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4" xlink:to="loc_us-gaap_EquityComponentDomain_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_1e9d4b55-80a5-4b4d-90fb-5640fe5057fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cbc5dd45-15b2-4a42-b53f-aaec7f3241c4" xlink:to="loc_us-gaap_EquityComponentDomain_1e9d4b55-80a5-4b4d-90fb-5640fe5057fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_5344cd3c-8d0b-4648-b0d1-4832ed9aed5f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1e9d4b55-80a5-4b4d-90fb-5640fe5057fb" xlink:to="loc_us-gaap_RetainedEarningsMember_5344cd3c-8d0b-4648-b0d1-4832ed9aed5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_8c4284bf-714f-44ae-b6c3-16a1aa5e1e7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1e9d4b55-80a5-4b4d-90fb-5640fe5057fb" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_8c4284bf-714f-44ae-b6c3-16a1aa5e1e7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_crl_ScheduleOfStockRepurchasesTable_d1fb8966-3454-4e43-9fd5-93cd9884f2e4" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_0d1cf7c2-b57a-4e36-8aad-51880cf2658d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_d81f20e8-1cd0-485c-b2ed-29df8e1b42b0" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_0d1cf7c2-b57a-4e36-8aad-51880cf2658d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_A2010ShareRepurchaseProgramMember_bec5e7c3-6a37-4ed4-8c35-83c0488ad8a3" xlink:href="crl-20221231.xsd#crl_A2010ShareRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareRepurchaseProgramDomain_0d1cf7c2-b57a-4e36-8aad-51880cf2658d" xlink:to="loc_crl_A2010ShareRepurchaseProgramMember_bec5e7c3-6a37-4ed4-8c35-83c0488ad8a3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSChangestoAccumulatedOtherComprehensiveIncomeLossNetofIncomeTaxesDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EQUITYANDNONCONTROLLINGINTERESTSChangestoAccumulatedOtherComprehensiveIncomeLossNetofIncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSChangestoAccumulatedOtherComprehensiveIncomeLossNetofIncomeTaxesDetails" xlink:type="extended" id="i502d73977fce47539713a0ccb06d9a2a_EQUITYANDNONCONTROLLINGINTERESTSChangestoAccumulatedOtherComprehensiveIncomeLossNetofIncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_82a22361-874a-48bd-8fa8-eac9e8317305" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_82a22361-874a-48bd-8fa8-eac9e8317305" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_659f776e-ccfe-4f20-a973-701486f8b2ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_659f776e-ccfe-4f20-a973-701486f8b2ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_f57a5142-49d6-44a6-86a5-eb01f95d7e6d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsBeforeTax_f57a5142-49d6-44a6-86a5-eb01f95d7e6d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_765fb60e-9978-4c1b-a5df-e43aa50d1072" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodBeforeTax_765fb60e-9978-4c1b-a5df-e43aa50d1072" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_a088e634-bc8e-439b-8329-acafd5a57fea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_a088e634-bc8e-439b-8329-acafd5a57fea" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_16147fea-10a0-46f4-9c8e-2651e19132d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_5c03ebb3-fa9d-4cd2-953b-fdf29b667140" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_16147fea-10a0-46f4-9c8e-2651e19132d6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_02786876-cabc-4912-b277-c29529b12ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_324fdedb-9fb3-4d9d-8e19-16467e7652e2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_82a22361-874a-48bd-8fa8-eac9e8317305" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_324fdedb-9fb3-4d9d-8e19-16467e7652e2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_421f5bfe-d758-4bac-b492-25dd8b042ae5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_324fdedb-9fb3-4d9d-8e19-16467e7652e2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_421f5bfe-d758-4bac-b492-25dd8b042ae5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_421f5bfe-d758-4bac-b492-25dd8b042ae5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_421f5bfe-d758-4bac-b492-25dd8b042ae5" xlink:to="loc_us-gaap_EquityComponentDomain_421f5bfe-d758-4bac-b492-25dd8b042ae5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_421f5bfe-d758-4bac-b492-25dd8b042ae5" xlink:to="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_9202dc76-3d8d-451d-ae3f-f113b75c9258" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_9202dc76-3d8d-451d-ae3f-f113b75c9258" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_6f4d8ffe-5f98-447d-9493-377b1455a3a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_6f4d8ffe-5f98-447d-9493-377b1455a3a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_b7cd579c-66e7-43d9-86d6-8549a67ef26d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_b7cd579c-66e7-43d9-86d6-8549a67ef26d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_48d33cdb-1644-4f72-a9b2-b019ebb090f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ed111353-3c03-4044-b32c-cd5fd6b8a508" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_48d33cdb-1644-4f72-a9b2-b019ebb090f2" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSNonredeemableandRedeemableNoncontrollingInterestNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EQUITYANDNONCONTROLLINGINTERESTSNonredeemableandRedeemableNoncontrollingInterestNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EQUITYANDNONCONTROLLINGINTERESTSNonredeemableandRedeemableNoncontrollingInterestNarrativeDetails" xlink:type="extended" id="if6bee4aafafe4aadab2d445192fbd3cb_EQUITYANDNONCONTROLLINGINTERESTSNonredeemableandRedeemableNoncontrollingInterestNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_f5805492-0c64-48c4-ae92-d1a3c42dd1e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_f5805492-0c64-48c4-ae92-d1a3c42dd1e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_c2a109d3-2f51-4691-9a36-4ae30f9d0da3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_c2a109d3-2f51-4691-9a36-4ae30f9d0da3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityRedemptionValue_611b8b15-5d66-4331-937c-759ca664c1d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RedeemableNoncontrollingInterestEquityRedemptionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityRedemptionValue_611b8b15-5d66-4331-937c-759ca664c1d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EquityMethodInvestmentIncreaseDecreaseInOwnershipPercentageByParent_97cf17d5-caae-489c-ae0f-f6f793246f88" xlink:href="crl-20221231.xsd#crl_EquityMethodInvestmentIncreaseDecreaseInOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_crl_EquityMethodInvestmentIncreaseDecreaseInOwnershipPercentageByParent_97cf17d5-caae-489c-ae0f-f6f793246f88" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesPurchaseOfInterestByParent_5d28a69c-a186-4b14-9acb-60708f37f598" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesPurchaseOfInterestByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesPurchaseOfInterestByParent_5d28a69c-a186-4b14-9acb-60708f37f598" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_686ba508-0a26-4261-bcd2-8d9a2df31382" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount_686ba508-0a26-4261-bcd2-8d9a2df31382" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_91e3ff9d-c18d-4e28-8eb3-2c2ed85666e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_7cfe8b19-c281-45a4-8c6e-c2e68004c329" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_91e3ff9d-c18d-4e28-8eb3-2c2ed85666e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_7e0a849b-43aa-41e3-a3c6-9cd678387509" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_91e3ff9d-c18d-4e28-8eb3-2c2ed85666e7" xlink:to="loc_srt_OwnershipAxis_7e0a849b-43aa-41e3-a3c6-9cd678387509" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_7e0a849b-43aa-41e3-a3c6-9cd678387509_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_7e0a849b-43aa-41e3-a3c6-9cd678387509" xlink:to="loc_srt_OwnershipDomain_7e0a849b-43aa-41e3-a3c6-9cd678387509_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_a153a77f-68a0-4a50-a3c3-a1464209759b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_7e0a849b-43aa-41e3-a3c6-9cd678387509" xlink:to="loc_srt_OwnershipDomain_a153a77f-68a0-4a50-a3c3-a1464209759b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VitalRiverMember_2da0b525-1e17-40a2-9871-53ece1f5c90e" xlink:href="crl-20221231.xsd#crl_VitalRiverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_a153a77f-68a0-4a50-a3c3-a1464209759b" xlink:to="loc_crl_VitalRiverMember_2da0b525-1e17-40a2-9871-53ece1f5c90e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SupplierMember_9aa31363-855d-4eeb-a335-85ec8d8fcb81" xlink:href="crl-20221231.xsd#crl_SupplierMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_a153a77f-68a0-4a50-a3c3-a1464209759b" xlink:to="loc_crl_SupplierMember_9aa31363-855d-4eeb-a335-85ec8d8fcb81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_23e1f603-8565-4b6d-80bc-ed72e84a11a3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_91e3ff9d-c18d-4e28-8eb3-2c2ed85666e7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_23e1f603-8565-4b6d-80bc-ed72e84a11a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_23e1f603-8565-4b6d-80bc-ed72e84a11a3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_23e1f603-8565-4b6d-80bc-ed72e84a11a3" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_23e1f603-8565-4b6d-80bc-ed72e84a11a3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9a301cf3-7623-4d58-8438-e24a5b4bd433" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_23e1f603-8565-4b6d-80bc-ed72e84a11a3" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9a301cf3-7623-4d58-8438-e24a5b4bd433" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_VitalRiverMember_1b88ad5d-2797-4e5a-b179-fec476243c32" xlink:href="crl-20221231.xsd#crl_VitalRiverMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9a301cf3-7623-4d58-8438-e24a5b4bd433" xlink:to="loc_crl_VitalRiverMember_1b88ad5d-2797-4e5a-b179-fec476243c32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SupplierMember_19c930ad-3b83-490b-ad04-eae03cd301aa" xlink:href="crl-20221231.xsd#crl_SupplierMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9a301cf3-7623-4d58-8438-e24a5b4bd433" xlink:to="loc_crl_SupplierMember_19c930ad-3b83-490b-ad04-eae03cd301aa" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/INCOMETAXESAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#INCOMETAXESAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/INCOMETAXESAdditionalInformationDetails" xlink:type="extended" id="i8446e138278f49d19a24ee7995d4049b_INCOMETAXESAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_16ff2f1e-260e-4c16-b394-cc74b34ec69d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_OperatingLossCarryforwards_16ff2f1e-260e-4c16-b394-cc74b34ec69d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_240993e2-661c-44f6-99b0-7d865d905777" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TaxCreditCarryforwardAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_240993e2-661c-44f6-99b0-7d865d905777" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_b13dfc82-1c31-4912-8f9c-e6a76c6aca8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_b13dfc82-1c31-4912-8f9c-e6a76c6aca8f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_e1ad4703-ba81-4bfb-8cfb-7ede17f80191" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_e1ad4703-ba81-4bfb-8cfb-7ede17f80191" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_Changeunrecognizedtaxbenefitsthatifrecognizedwouldaffecttheeffectivetaxrate._37888b56-a47e-4a06-9839-e2229549ea4a" xlink:href="crl-20221231.xsd#crl_Changeunrecognizedtaxbenefitsthatifrecognizedwouldaffecttheeffectivetaxrate."/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_crl_Changeunrecognizedtaxbenefitsthatifrecognizedwouldaffecttheeffectivetaxrate._37888b56-a47e-4a06-9839-e2229549ea4a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible_22de0288-7853-4b2b-9724-4bc714f9a508" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible_22de0288-7853-4b2b-9724-4bc714f9a508" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued_b32ba407-b991-4d5d-a451-53c14469d954" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued_b32ba407-b991-4d5d-a451-53c14469d954" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued_0ca4d566-0f1f-4d57-b383-b2356a006b95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued_0ca4d566-0f1f-4d57-b383-b2356a006b95" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidTaxes_a09cc791-e66c-4749-8493-9e52c3c2a622" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_PrepaidTaxes_a09cc791-e66c-4749-8493-9e52c3c2a622" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedIncomeTaxes_93999452-abdc-40e9-9475-9be944aa3446" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_AccruedIncomeTaxes_93999452-abdc-40e9-9475-9be944aa3446" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_12b4feb5-311d-4c10-830f-dcef2dcba43a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_2c94cdc8-0198-4d1d-8aed-800f76398fc2" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_12b4feb5-311d-4c10-830f-dcef2dcba43a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_c53db032-33f0-4b7f-aae4-7b9f1c841dbf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_12b4feb5-311d-4c10-830f-dcef2dcba43a" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_c53db032-33f0-4b7f-aae4-7b9f1c841dbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_c53db032-33f0-4b7f-aae4-7b9f1c841dbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_c53db032-33f0-4b7f-aae4-7b9f1c841dbf" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_c53db032-33f0-4b7f-aae4-7b9f1c841dbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_a1036402-9f1c-406f-8243-44235db8335b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_c53db032-33f0-4b7f-aae4-7b9f1c841dbf" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_a1036402-9f1c-406f-8243-44235db8335b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_dd5ce515-e6e4-4a86-9f93-1a6b699e3945" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_a1036402-9f1c-406f-8243-44235db8335b" xlink:to="loc_us-gaap_ForeignCountryMember_dd5ce515-e6e4-4a86-9f93-1a6b699e3945" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OperatingLossCarryforwardsByExpirationPeriodAxis_835b6f69-d6a3-460d-8dbc-4330950a749b" xlink:href="crl-20221231.xsd#crl_OperatingLossCarryforwardsByExpirationPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_12b4feb5-311d-4c10-830f-dcef2dcba43a" xlink:to="loc_crl_OperatingLossCarryforwardsByExpirationPeriodAxis_835b6f69-d6a3-460d-8dbc-4330950a749b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_835b6f69-d6a3-460d-8dbc-4330950a749b_default" xlink:href="crl-20221231.xsd#crl_OperatingLossCarryforwardsByExpirationPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_crl_OperatingLossCarryforwardsByExpirationPeriodAxis_835b6f69-d6a3-460d-8dbc-4330950a749b" xlink:to="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_835b6f69-d6a3-460d-8dbc-4330950a749b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_c4672d55-dd04-4db0-9978-0ecea811159a" xlink:href="crl-20221231.xsd#crl_OperatingLossCarryforwardsByExpirationPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_crl_OperatingLossCarryforwardsByExpirationPeriodAxis_835b6f69-d6a3-460d-8dbc-4330950a749b" xlink:to="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_c4672d55-dd04-4db0-9978-0ecea811159a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_NetOperatingLossCarryforwardExpiringNextYearMember_137c50ce-b2f8-4cda-b831-69527db71a04" xlink:href="crl-20221231.xsd#crl_NetOperatingLossCarryforwardExpiringNextYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_c4672d55-dd04-4db0-9978-0ecea811159a" xlink:to="loc_crl_NetOperatingLossCarryforwardExpiringNextYearMember_137c50ce-b2f8-4cda-b831-69527db71a04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_CarriedForwardIndefinitelyMember_f97564e3-3eaf-454a-be48-b74c394e30a2" xlink:href="crl-20221231.xsd#crl_CarriedForwardIndefinitelyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_OperatingLossCarryforwardsByExpirationPeriodDomain_c4672d55-dd04-4db0-9978-0ecea811159a" xlink:to="loc_crl_CarriedForwardIndefinitelyMember_f97564e3-3eaf-454a-be48-b74c394e30a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TaxCreditCarryforwardsByExpirationPeriodAxis_88b20d42-a58e-486e-bf09-c57e17e6be94" xlink:href="crl-20221231.xsd#crl_TaxCreditCarryforwardsByExpirationPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_12b4feb5-311d-4c10-830f-dcef2dcba43a" xlink:to="loc_crl_TaxCreditCarryforwardsByExpirationPeriodAxis_88b20d42-a58e-486e-bf09-c57e17e6be94" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TaxCreditCarryforwardsByExpirationPeriodDomain_88b20d42-a58e-486e-bf09-c57e17e6be94_default" xlink:href="crl-20221231.xsd#crl_TaxCreditCarryforwardsByExpirationPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_crl_TaxCreditCarryforwardsByExpirationPeriodAxis_88b20d42-a58e-486e-bf09-c57e17e6be94" xlink:to="loc_crl_TaxCreditCarryforwardsByExpirationPeriodDomain_88b20d42-a58e-486e-bf09-c57e17e6be94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TaxCreditCarryforwardsByExpirationPeriodDomain_3923f329-3daf-4795-93b8-b349ea76cd4a" xlink:href="crl-20221231.xsd#crl_TaxCreditCarryforwardsByExpirationPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_crl_TaxCreditCarryforwardsByExpirationPeriodAxis_88b20d42-a58e-486e-bf09-c57e17e6be94" xlink:to="loc_crl_TaxCreditCarryforwardsByExpirationPeriodDomain_3923f329-3daf-4795-93b8-b349ea76cd4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TaxCreditCarryforwardsExpirationRange2Member_9712f80a-2b8b-48fa-9a5f-32f3204d6b5d" xlink:href="crl-20221231.xsd#crl_TaxCreditCarryforwardsExpirationRange2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_crl_TaxCreditCarryforwardsByExpirationPeriodDomain_3923f329-3daf-4795-93b8-b349ea76cd4a" xlink:to="loc_crl_TaxCreditCarryforwardsExpirationRange2Member_9712f80a-2b8b-48fa-9a5f-32f3204d6b5d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EMPLOYEEBENEFITPLANSAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EMPLOYEEBENEFITPLANSAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EMPLOYEEBENEFITPLANSAdditionalInformationDetails" xlink:type="extended" id="ib9a577612ab2463dba2df498fa29c2f7_EMPLOYEEBENEFITPLANSAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_5f0c83b6-4284-4e2d-8c1e-1e9e71f64bed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_5f0c83b6-4284-4e2d-8c1e-1e9e71f64bed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_6eb29934-ac10-4eba-921f-2e9eb25f20c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_6eb29934-ac10-4eba-921f-2e9eb25f20c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_6ff247a3-78f9-4c7c-a119-b3131b8b66ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_6ff247a3-78f9-4c7c-a119-b3131b8b66ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_7ddb13da-8e6b-43ea-8f30-f1b1e80528dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_7ddb13da-8e6b-43ea-8f30-f1b1e80528dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_b98b8405-36cd-4211-9e74-a8a981651890" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_b98b8405-36cd-4211-9e74-a8a981651890" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_fdb6d5da-8449-457c-8601-f70bb515b0eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_fdb6d5da-8449-457c-8601-f70bb515b0eb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DeferredCompensationArrangementwithIndividualDeferralPeriod_2039191c-441c-4c3c-9d9e-eea0372f826a" xlink:href="crl-20221231.xsd#crl_DeferredCompensationArrangementwithIndividualDeferralPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DeferredCompensationArrangementwithIndividualDeferralPeriod_2039191c-441c-4c3c-9d9e-eea0372f826a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_d797738c-1461-4743-b5bc-d36a1b8bae64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_d797738c-1461-4743-b5bc-d36a1b8bae64" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DeferredCompensationArrangementwithIndividualPeriodofHighestConsecutiveYearsofCompensationUsedforDeterminationofExecutiveSupplementalLifeInsuranceRetirementPlanBenefit_53b3c9ca-ab36-43c5-bcb8-0ffd55e80f35" xlink:href="crl-20221231.xsd#crl_DeferredCompensationArrangementwithIndividualPeriodofHighestConsecutiveYearsofCompensationUsedforDeterminationofExecutiveSupplementalLifeInsuranceRetirementPlanBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DeferredCompensationArrangementwithIndividualPeriodofHighestConsecutiveYearsofCompensationUsedforDeterminationofExecutiveSupplementalLifeInsuranceRetirementPlanBenefit_53b3c9ca-ab36-43c5-bcb8-0ffd55e80f35" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_aa886d3b-8b03-4749-a47a-5840542c70eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense_aa886d3b-8b03-4749-a47a-5840542c70eb" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DeferredCompensationArrangementWithIndividualNonCashSettlementCharges_c9ddbfc8-bf16-4c76-bff8-da2229bf046f" xlink:href="crl-20221231.xsd#crl_DeferredCompensationArrangementWithIndividualNonCashSettlementCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DeferredCompensationArrangementWithIndividualNonCashSettlementCharges_c9ddbfc8-bf16-4c76-bff8-da2229bf046f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashSurrenderValueOfLifeInsurance_14396500-c8d9-4787-96e8-b884f89b32d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashSurrenderValueOfLifeInsurance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_CashSurrenderValueOfLifeInsurance_14396500-c8d9-4787-96e8-b884f89b32d6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DefinedBenefitPlanIncreaseDecreaseInProjectedBenefitObligationFrom25BasisPointChangeInDiscountRate_d5a23dc6-3672-418b-bed2-873b362ba37f" xlink:href="crl-20221231.xsd#crl_DefinedBenefitPlanIncreaseDecreaseInProjectedBenefitObligationFrom25BasisPointChangeInDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DefinedBenefitPlanIncreaseDecreaseInProjectedBenefitObligationFrom25BasisPointChangeInDiscountRate_d5a23dc6-3672-418b-bed2-873b362ba37f" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_Sensitivityofexpectedrateofreturnonplanassetspercentchange_5cdd41ff-62c3-4b82-9148-f70d97ebe621" xlink:href="crl-20221231.xsd#crl_Sensitivityofexpectedrateofreturnonplanassetspercentchange"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_Sensitivityofexpectedrateofreturnonplanassetspercentchange_5cdd41ff-62c3-4b82-9148-f70d97ebe621" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_Sensitivityofchangeinexpectedrateofreturnannualpensionexpenseamount_5a97291b-6b7f-410f-a1f2-d8451255a8d5" xlink:href="crl-20221231.xsd#crl_Sensitivityofchangeinexpectedrateofreturnannualpensionexpenseamount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_Sensitivityofchangeinexpectedrateofreturnannualpensionexpenseamount_5a97291b-6b7f-410f-a1f2-d8451255a8d5" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DefinedBenefitPlanActuarialGainLossChangeinMortalityAssumptions_78c5aba2-87ab-4db9-9bf1-0503284488d0" xlink:href="crl-20221231.xsd#crl_DefinedBenefitPlanActuarialGainLossChangeinMortalityAssumptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DefinedBenefitPlanActuarialGainLossChangeinMortalityAssumptions_78c5aba2-87ab-4db9-9bf1-0503284488d0" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_3485c2eb-cae9-49f3-8d38-29bd8bb042df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_3485c2eb-cae9-49f3-8d38-29bd8bb042df" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_c4fb607a-a505-4395-8b58-9da03233a301" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_c4fb607a-a505-4395-8b58-9da03233a301" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DefinedBenefitPlanContributionsByEmployerToParticipantsOutsideOfPlanAssets_6f18e4bc-c868-4f50-8fb7-3f287e73b13e" xlink:href="crl-20221231.xsd#crl_DefinedBenefitPlanContributionsByEmployerToParticipantsOutsideOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_crl_DefinedBenefitPlanContributionsByEmployerToParticipantsOutsideOfPlanAssets_6f18e4bc-c868-4f50-8fb7-3f287e73b13e" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_325c6353-19e1-48be-b4fa-96c1c1585138" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_325c6353-19e1-48be-b4fa-96c1c1585138" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_e47ae2aa-c960-4702-9788-998800ad1098" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_39f25032-0722-4267-b700-05d724ac1295" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_39f25032-0722-4267-b700-05d724ac1295" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_39f25032-0722-4267-b700-05d724ac1295_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_39f25032-0722-4267-b700-05d724ac1295" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_39f25032-0722-4267-b700-05d724ac1295_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_66e5fd51-8421-4783-afab-eb979a3bee6b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_39f25032-0722-4267-b700-05d724ac1295" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_66e5fd51-8421-4783-afab-eb979a3bee6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_2dadae4a-8d61-4f58-bbec-f565461ad7ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_66e5fd51-8421-4783-afab-eb979a3bee6b" xlink:to="loc_us-gaap_EquitySecuritiesMember_2dadae4a-8d61-4f58-bbec-f565461ad7ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_e91dc2ec-3524-4f4b-8131-0a658e5127f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_66e5fd51-8421-4783-afab-eb979a3bee6b" xlink:to="loc_us-gaap_DebtSecuritiesMember_e91dc2ec-3524-4f4b-8131-0a658e5127f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherPlanAssetCategoriesMember_bf86a935-9f0d-4601-b781-63d21e1fa1fb" xlink:href="crl-20221231.xsd#crl_OtherPlanAssetCategoriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_66e5fd51-8421-4783-afab-eb979a3bee6b" xlink:to="loc_crl_OtherPlanAssetCategoriesMember_bf86a935-9f0d-4601-b781-63d21e1fa1fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_7b09870c-1082-4103-9865-a44031d1e7cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_7b09870c-1082-4103-9865-a44031d1e7cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_7b09870c-1082-4103-9865-a44031d1e7cb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_7b09870c-1082-4103-9865-a44031d1e7cb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_7b09870c-1082-4103-9865-a44031d1e7cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9a463b11-5ac7-41f8-9cc0-0205fd7ddaef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_7b09870c-1082-4103-9865-a44031d1e7cb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9a463b11-5ac7-41f8-9cc0-0205fd7ddaef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_9490349b-78ba-421f-a056-0d386dc15056" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_9a463b11-5ac7-41f8-9cc0-0205fd7ddaef" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_9490349b-78ba-421f-a056-0d386dc15056" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationAxis_871b4c02-e5b4-44c3-a227-8f91a1c518e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanSponsorLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationAxis_871b4c02-e5b4-44c3-a227-8f91a1c518e4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_871b4c02-e5b4-44c3-a227-8f91a1c518e4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_871b4c02-e5b4-44c3-a227-8f91a1c518e4" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_871b4c02-e5b4-44c3-a227-8f91a1c518e4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanSponsorLocationDomain_e1e1a39a-27d9-4138-8c3e-f69328ec2abd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanSponsorLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationAxis_871b4c02-e5b4-44c3-a227-8f91a1c518e4" xlink:to="loc_us-gaap_RetirementPlanSponsorLocationDomain_e1e1a39a-27d9-4138-8c3e-f69328ec2abd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignPlanMember_9bd3ce24-8486-43ba-9ed6-eba34a978a5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanSponsorLocationDomain_e1e1a39a-27d9-4138-8c3e-f69328ec2abd" xlink:to="loc_us-gaap_ForeignPlanMember_9bd3ce24-8486-43ba-9ed6-eba34a978a5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanFundingStatusAxis_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanFundingStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:to="loc_us-gaap_RetirementPlanFundingStatusAxis_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanFundingStatusDomain_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanFundingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanFundingStatusAxis_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4" xlink:to="loc_us-gaap_RetirementPlanFundingStatusDomain_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanFundingStatusDomain_37232947-462c-4a35-a31c-bf864be52423" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanFundingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanFundingStatusAxis_17ab4ffa-41ac-4c00-bad9-3aa34788f6c4" xlink:to="loc_us-gaap_RetirementPlanFundingStatusDomain_37232947-462c-4a35-a31c-bf864be52423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FundedPlanMember_2ce579fd-91ce-4db0-8605-64bac12bf996" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FundedPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanFundingStatusDomain_37232947-462c-4a35-a31c-bf864be52423" xlink:to="loc_us-gaap_FundedPlanMember_2ce579fd-91ce-4db0-8605-64bac12bf996" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_32042aad-d372-4919-96ed-93cc130fb6aa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_bdc798f2-1f23-4859-a9f4-390bdff3dc4f" xlink:to="loc_srt_TitleOfIndividualAxis_32042aad-d372-4919-96ed-93cc130fb6aa" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_32042aad-d372-4919-96ed-93cc130fb6aa_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_32042aad-d372-4919-96ed-93cc130fb6aa" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_32042aad-d372-4919-96ed-93cc130fb6aa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_74db9f7f-0808-4cf1-81a7-aa3e6b592248" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_32042aad-d372-4919-96ed-93cc130fb6aa" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_74db9f7f-0808-4cf1-81a7-aa3e6b592248" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExecutiveOfficerMember_334efea4-368a-45e0-a19b-0f07bf06c20a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_74db9f7f-0808-4cf1-81a7-aa3e6b592248" xlink:to="loc_srt_ExecutiveOfficerMember_334efea4-368a-45e0-a19b-0f07bf06c20a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EMPLOYEEBENEFITPLANSFairValueofCompanysPensionPlanAssetsbyAssetCategoryDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EMPLOYEEBENEFITPLANSFairValueofCompanysPensionPlanAssetsbyAssetCategoryDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EMPLOYEEBENEFITPLANSFairValueofCompanysPensionPlanAssetsbyAssetCategoryDetails" xlink:type="extended" id="i5d3a62041e1147d28e695ec41fc92a32_EMPLOYEEBENEFITPLANSFairValueofCompanysPensionPlanAssetsbyAssetCategoryDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_941c893d-010c-43fe-a6be-6aedea812b1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_205c58fd-0efc-4493-a8dd-6bfe37928b38" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_941c893d-010c-43fe-a6be-6aedea812b1b" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_205c58fd-0efc-4493-a8dd-6bfe37928b38" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_54e2cdc7-d462-4770-ba87-a0a04ee3e502" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_941c893d-010c-43fe-a6be-6aedea812b1b" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_54e2cdc7-d462-4770-ba87-a0a04ee3e502" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_82948324-18ef-4606-b49f-abd8a17883ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_54e2cdc7-d462-4770-ba87-a0a04ee3e502" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_82948324-18ef-4606-b49f-abd8a17883ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_82948324-18ef-4606-b49f-abd8a17883ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_82948324-18ef-4606-b49f-abd8a17883ea" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_82948324-18ef-4606-b49f-abd8a17883ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_05f5ebf9-01dc-4694-b15b-4ce10d41e03d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_82948324-18ef-4606-b49f-abd8a17883ea" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_05f5ebf9-01dc-4694-b15b-4ce10d41e03d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_5efbab63-b56a-4fd2-b1cf-cffbde425c23" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_05f5ebf9-01dc-4694-b15b-4ce10d41e03d" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_5efbab63-b56a-4fd2-b1cf-cffbde425c23" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_f9f5ed9f-f311-450e-8263-03907a563f82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_05f5ebf9-01dc-4694-b15b-4ce10d41e03d" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_f9f5ed9f-f311-450e-8263-03907a563f82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_516af4ee-2047-43f0-bfe7-0964b8429641" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_05f5ebf9-01dc-4694-b15b-4ce10d41e03d" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_516af4ee-2047-43f0-bfe7-0964b8429641" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5de3a7e7-b59a-4e1e-889b-30ef0709d742" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_54e2cdc7-d462-4770-ba87-a0a04ee3e502" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5de3a7e7-b59a-4e1e-889b-30ef0709d742" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_5de3a7e7-b59a-4e1e-889b-30ef0709d742_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5de3a7e7-b59a-4e1e-889b-30ef0709d742" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_5de3a7e7-b59a-4e1e-889b-30ef0709d742_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5de3a7e7-b59a-4e1e-889b-30ef0709d742" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsMember_c267751d-53ab-4197-bc64-37f2b9206089" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:to="loc_us-gaap_CashAndCashEquivalentsMember_c267751d-53ab-4197-bc64-37f2b9206089" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_347b4440-5fcc-46bb-8a02-ecbb4818fa45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:to="loc_us-gaap_EquitySecuritiesMember_347b4440-5fcc-46bb-8a02-ecbb4818fa45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_81e81300-b625-40dc-8234-d1c98666947d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:to="loc_us-gaap_DebtSecuritiesMember_81e81300-b625-40dc-8234-d1c98666947d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityFundsMember_ee80312c-c9a9-4532-b780-c30806390fc7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:to="loc_us-gaap_EquityFundsMember_ee80312c-c9a9-4532-b780-c30806390fc7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_OtherPlanAssetCategoriesMember_c4f3282b-f759-4d5a-a0cd-e8b73a5604fa" xlink:href="crl-20221231.xsd#crl_OtherPlanAssetCategoriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_7b986bdf-8731-493c-84ee-6dcdb3a5fdc3" xlink:to="loc_crl_OtherPlanAssetCategoriesMember_c4f3282b-f759-4d5a-a0cd-e8b73a5604fa" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/EMPLOYEEBENEFITPLANSEstimatedFutureBenefitPaymentsDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#EMPLOYEEBENEFITPLANSEstimatedFutureBenefitPaymentsDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/EMPLOYEEBENEFITPLANSEstimatedFutureBenefitPaymentsDetails" xlink:type="extended" id="i9207c67e1c0d43b1bd9a5b735711457a_EMPLOYEEBENEFITPLANSEstimatedFutureBenefitPaymentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_c09f41bf-b4fd-4ca5-80aa-c9a5875c039d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_c09f41bf-b4fd-4ca5-80aa-c9a5875c039d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_0bc13bc2-46f7-40b5-b5ae-90cb6a2736c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_0bc13bc2-46f7-40b5-b5ae-90cb6a2736c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_7ec36e8e-99a0-4f2c-b6f0-44442f686687" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_7ec36e8e-99a0-4f2c-b6f0-44442f686687" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_2de15409-52d2-4f0b-b806-fb307181245e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_2de15409-52d2-4f0b-b806-fb307181245e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_ffb7bc46-bbb6-4fff-b66b-7d7bc460cdbe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_ffb7bc46-bbb6-4fff-b66b-7d7bc460cdbe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_231d91ce-91b3-4495-a0bb-a1513ed281e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_231d91ce-91b3-4495-a0bb-a1513ed281e8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_abca20a1-fd39-4cfd-8699-0eb53735f155" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bc1408fd-339d-429d-a676-a16db48d2354" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_abca20a1-fd39-4cfd-8699-0eb53735f155" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_9cd38017-11ee-4ad3-9023-e668b0b8b189" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_abca20a1-fd39-4cfd-8699-0eb53735f155" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_9cd38017-11ee-4ad3-9023-e668b0b8b189" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9cd38017-11ee-4ad3-9023-e668b0b8b189_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9cd38017-11ee-4ad3-9023-e668b0b8b189" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9cd38017-11ee-4ad3-9023-e668b0b8b189_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_1548c7dc-8c27-454f-8858-d2b6b6788124" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9cd38017-11ee-4ad3-9023-e668b0b8b189" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_1548c7dc-8c27-454f-8858-d2b6b6788124" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_8f0b0a4d-56ec-4e42-87b6-e41854420f49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_1548c7dc-8c27-454f-8858-d2b6b6788124" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_8f0b0a4d-56ec-4e42-87b6-e41854420f49" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/STOCKBASEDCOMPENSATIONAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#STOCKBASEDCOMPENSATIONAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/STOCKBASEDCOMPENSATIONAdditionalInformationDetails" xlink:type="extended" id="idb19877b18024de6b5a8f6c57522cf75_STOCKBASEDCOMPENSATIONAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_2eb18443-435a-48f8-bc83-03687c9b60eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_2eb18443-435a-48f8-bc83-03687c9b60eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_6a4877e0-ec61-4371-8d2a-ede8721555dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_6a4877e0-ec61-4371-8d2a-ede8721555dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesPerEmployeeAvailabletoPurchase_b695414a-7a5a-425b-be6b-e51587a3782a" xlink:href="crl-20221231.xsd#crl_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesPerEmployeeAvailabletoPurchase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_crl_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesPerEmployeeAvailabletoPurchase_b695414a-7a5a-425b-be6b-e51587a3782a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_89361085-d029-4ad8-978b-81cd09929af2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_89361085-d029-4ad8-978b-81cd09929af2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_52a00920-a892-4932-91fe-ac7df01f4771" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_52a00920-a892-4932-91fe-ac7df01f4771" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_46f39b6d-6ef4-47e2-8306-49dd0b72cee6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_46f39b6d-6ef4-47e2-8306-49dd0b72cee6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_5e72b363-af53-4373-8519-a3fa0212dc67" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_5e72b363-af53-4373-8519-a3fa0212dc67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_EmployeeServiceSharebasedCompensationNonvestedAwardsTotalCompensationCostNotyetRecognizedPeriodforRecognitioninYears_e2eaa20a-f13a-4f48-bdaf-1ee48092b82e" xlink:href="crl-20221231.xsd#crl_EmployeeServiceSharebasedCompensationNonvestedAwardsTotalCompensationCostNotyetRecognizedPeriodforRecognitioninYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_crl_EmployeeServiceSharebasedCompensationNonvestedAwardsTotalCompensationCostNotyetRecognizedPeriodforRecognitioninYears_e2eaa20a-f13a-4f48-bdaf-1ee48092b82e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_473bf378-c8da-45fc-bf51-098b7ffdb10f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_473bf378-c8da-45fc-bf51-098b7ffdb10f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_4f96356b-1d6e-461a-909f-38177d6221a3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_4f96356b-1d6e-461a-909f-38177d6221a3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_9d018d78-e6a9-49c6-96b9-8b9a9a1bd4c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_9d018d78-e6a9-49c6-96b9-8b9a9a1bd4c4" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_MaxPsuShares_e9cd3fa9-2d40-489b-983b-3f0e56a18fab" xlink:href="crl-20221231.xsd#crl_MaxPsuShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_crl_MaxPsuShares_e9cd3fa9-2d40-489b-983b-3f0e56a18fab" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_552d2769-32c0-42dc-acea-5e1133279bb4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_552d2769-32c0-42dc-acea-5e1133279bb4" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d6c5459f-fc3b-4f2f-ad2b-c42ff02730ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d6c5459f-fc3b-4f2f-ad2b-c42ff02730ad" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_352ee867-6e6f-44ca-9b73-1de376451396" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_352ee867-6e6f-44ca-9b73-1de376451396" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76f51c59-5b0f-4c38-a86f-4b6b0b0e7139" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_18ab3591-51da-4195-be61-489659c5dc73" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76f51c59-5b0f-4c38-a86f-4b6b0b0e7139" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_cd6bfd96-4cba-45f7-888b-d6bec62acee5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76f51c59-5b0f-4c38-a86f-4b6b0b0e7139" xlink:to="loc_us-gaap_AwardTypeAxis_cd6bfd96-4cba-45f7-888b-d6bec62acee5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_cd6bfd96-4cba-45f7-888b-d6bec62acee5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_cd6bfd96-4cba-45f7-888b-d6bec62acee5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_cd6bfd96-4cba-45f7-888b-d6bec62acee5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_cd6bfd96-4cba-45f7-888b-d6bec62acee5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_d148c698-0d97-408c-99b0-c08a5077532b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:to="loc_us-gaap_EmployeeStockOptionMember_d148c698-0d97-408c-99b0-c08a5077532b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_ef50e78c-452b-408f-aafe-54b4e66f008f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:to="loc_us-gaap_RestrictedStockMember_ef50e78c-452b-408f-aafe-54b4e66f008f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_6bf68e0c-8f74-46e7-bf3b-8a7f78eafbcb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_6bf68e0c-8f74-46e7-bf3b-8a7f78eafbcb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_e4607cf7-c459-4991-80d4-d7f811c045dd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_334ad9e1-9ec9-4969-99ba-209818230927" xlink:to="loc_us-gaap_PerformanceSharesMember_e4607cf7-c459-4991-80d4-d7f811c045dd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_59dc7c6f-7da4-44b7-887e-c622441e7457" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76f51c59-5b0f-4c38-a86f-4b6b0b0e7139" xlink:to="loc_srt_RangeAxis_59dc7c6f-7da4-44b7-887e-c622441e7457" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_59dc7c6f-7da4-44b7-887e-c622441e7457_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_59dc7c6f-7da4-44b7-887e-c622441e7457" xlink:to="loc_srt_RangeMember_59dc7c6f-7da4-44b7-887e-c622441e7457_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_73b99cd9-86f4-4a6b-896d-b70868a3b8a9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_59dc7c6f-7da4-44b7-887e-c622441e7457" xlink:to="loc_srt_RangeMember_73b99cd9-86f4-4a6b-896d-b70868a3b8a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_63fa5bae-acc3-4c7b-b781-c4f9697924e0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_73b99cd9-86f4-4a6b-896d-b70868a3b8a9" xlink:to="loc_srt_MinimumMember_63fa5bae-acc3-4c7b-b781-c4f9697924e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3b7c9586-20a3-4144-bd40-47cf516b1b8d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_73b99cd9-86f4-4a6b-896d-b70868a3b8a9" xlink:to="loc_srt_MaximumMember_3b7c9586-20a3-4144-bd40-47cf516b1b8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_4042abfc-55a9-4e16-bb43-d644f109741b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_76f51c59-5b0f-4c38-a86f-4b6b0b0e7139" xlink:to="loc_srt_TitleOfIndividualAxis_4042abfc-55a9-4e16-bb43-d644f109741b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_4042abfc-55a9-4e16-bb43-d644f109741b_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_4042abfc-55a9-4e16-bb43-d644f109741b" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_4042abfc-55a9-4e16-bb43-d644f109741b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3232929d-e889-4fb8-a28b-f5954af08f7f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_4042abfc-55a9-4e16-bb43-d644f109741b" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3232929d-e889-4fb8-a28b-f5954af08f7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_PerformanceSharesGranteeGroupTwoMember_9e45fcb6-d475-47e9-9b85-acc9ee4f0edd" xlink:href="crl-20221231.xsd#crl_PerformanceSharesGranteeGroupTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_3232929d-e889-4fb8-a28b-f5954af08f7f" xlink:to="loc_crl_PerformanceSharesGranteeGroupTwoMember_9e45fcb6-d475-47e9-9b85-acc9ee4f0edd" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/STOCKBASEDCOMPENSATIONFinancialStatementLineItemsinWhichStockBasedCompensationisLocatedDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#STOCKBASEDCOMPENSATIONFinancialStatementLineItemsinWhichStockBasedCompensationisLocatedDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/STOCKBASEDCOMPENSATIONFinancialStatementLineItemsinWhichStockBasedCompensationisLocatedDetails" xlink:type="extended" id="i9a260a61f2eb47e991106406f13a16f2_STOCKBASEDCOMPENSATIONFinancialStatementLineItemsinWhichStockBasedCompensationisLocatedDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_420d846f-a686-4f5a-a58c-9ed62fc22add" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_c68a4345-c55b-435d-bc1e-1241909017f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_420d846f-a686-4f5a-a58c-9ed62fc22add" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_c68a4345-c55b-435d-bc1e-1241909017f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_7e08ed4e-8d78-4958-9b69-67237dd98e9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_420d846f-a686-4f5a-a58c-9ed62fc22add" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_7e08ed4e-8d78-4958-9b69-67237dd98e9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_4188af47-6b09-469e-8d55-ab74fe9c0fac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_420d846f-a686-4f5a-a58c-9ed62fc22add" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_4188af47-6b09-469e-8d55-ab74fe9c0fac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_32936060-218c-4667-9760-4bede63f9651" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_420d846f-a686-4f5a-a58c-9ed62fc22add" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_32936060-218c-4667-9760-4bede63f9651" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_a30833ad-d187-4343-88ba-5e47706edcdc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_32936060-218c-4667-9760-4bede63f9651" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_a30833ad-d187-4343-88ba-5e47706edcdc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a30833ad-d187-4343-88ba-5e47706edcdc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a30833ad-d187-4343-88ba-5e47706edcdc" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a30833ad-d187-4343-88ba-5e47706edcdc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_94db1f76-2d96-4d5a-95be-d025bd6e3dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a30833ad-d187-4343-88ba-5e47706edcdc" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_94db1f76-2d96-4d5a-95be-d025bd6e3dbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_162d7ed8-9092-4ea9-b1c1-1a7d295c28de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_94db1f76-2d96-4d5a-95be-d025bd6e3dbd" xlink:to="loc_us-gaap_CostOfSalesMember_162d7ed8-9092-4ea9-b1c1-1a7d295c28de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_07aafc9a-6078-498e-931c-4c1b82fe33d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_94db1f76-2d96-4d5a-95be-d025bd6e3dbd" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_07aafc9a-6078-498e-931c-4c1b82fe33d3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/STOCKBASEDCOMPENSATIONRestrictedStockandRestrictedStockUnitsActivityDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#STOCKBASEDCOMPENSATIONRestrictedStockandRestrictedStockUnitsActivityDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/STOCKBASEDCOMPENSATIONRestrictedStockandRestrictedStockUnitsActivityDetails" xlink:type="extended" id="ie56531a62dea479584d8e639893484a3_STOCKBASEDCOMPENSATIONRestrictedStockandRestrictedStockUnitsActivityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5c96ba63-2697-4610-ac6a-10007abbe112" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5c96ba63-2697-4610-ac6a-10007abbe112" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_034125d2-72b0-412d-a928-43bcd7711b27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_034125d2-72b0-412d-a928-43bcd7711b27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_dc31a0fa-d819-4683-ac8f-a20995673291" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_dc31a0fa-d819-4683-ac8f-a20995673291" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a66af75b-f774-4829-9fd4-7b7db2cffe9c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_a66af75b-f774-4829-9fd4-7b7db2cffe9c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_66867b32-3b23-4c67-b158-b0160b225ec8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_8eeefec2-b9ab-4725-b64b-446db9f02024" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_66867b32-3b23-4c67-b158-b0160b225ec8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_4a0a90de-4f84-49be-8d4d-f7ed8f9d13aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5c96ba63-2697-4610-ac6a-10007abbe112" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_a192f4ab-b2cc-4b52-a6c6-90c7ef0fde79" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_a192f4ab-b2cc-4b52-a6c6-90c7ef0fde79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_358f110d-74d3-43a4-a05f-fa0cc7f1a0aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_358f110d-74d3-43a4-a05f-fa0cc7f1a0aa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_158148d8-2e21-41c8-8192-440003d19d83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_158148d8-2e21-41c8-8192-440003d19d83" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_1d44b8de-69df-4c58-ba3a-37b2c62bcae0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_8474424c-5857-4e75-87a6-75981f846f72" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_1d44b8de-69df-4c58-ba3a-37b2c62bcae0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_9f8852c7-7eb6-42ad-b15f-5b2e3f9727bf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9f1c680f-4358-4e41-b648-415d38993458" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5c96ba63-2697-4610-ac6a-10007abbe112" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9f1c680f-4358-4e41-b648-415d38993458" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9f1c680f-4358-4e41-b648-415d38993458" xlink:to="loc_us-gaap_AwardTypeAxis_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f726b76c-00c1-4087-b0c9-07a6d1dc9f89" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_f14b8eaf-b994-4d8e-b2c2-52ed9fc03e42" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f726b76c-00c1-4087-b0c9-07a6d1dc9f89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_RestrictedStockandRestrictedStockUnitsMember_c385506c-a08c-45fb-b567-552e231247ec" xlink:href="crl-20221231.xsd#crl_RestrictedStockandRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f726b76c-00c1-4087-b0c9-07a6d1dc9f89" xlink:to="loc_crl_RestrictedStockandRestrictedStockUnitsMember_c385506c-a08c-45fb-b567-552e231247ec" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/STOCKBASEDCOMPENSATIONPerformanceBasedStockAwardProgramDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#STOCKBASEDCOMPENSATIONPerformanceBasedStockAwardProgramDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/STOCKBASEDCOMPENSATIONPerformanceBasedStockAwardProgramDetails" xlink:type="extended" id="i55a9dec43494457e91bef5d2d3a45e0e_STOCKBASEDCOMPENSATIONPerformanceBasedStockAwardProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_169a189f-ca55-4cb5-889a-0d4ac460c321" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_4a47edc6-7282-4d15-9055-8f69d0efa514" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_169a189f-ca55-4cb5-889a-0d4ac460c321" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_4a47edc6-7282-4d15-9055-8f69d0efa514" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_94d96c18-3924-4f58-a2d3-734190efdc91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_169a189f-ca55-4cb5-889a-0d4ac460c321" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_94d96c18-3924-4f58-a2d3-734190efdc91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_169a189f-ca55-4cb5-889a-0d4ac460c321" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_f2538038-c6b5-4cbc-b47e-5930a19abd86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_f2538038-c6b5-4cbc-b47e-5930a19abd86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_1ebb6c47-15d4-4b7b-99e7-e9e2742e6dc3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_1ebb6c47-15d4-4b7b-99e7-e9e2742e6dc3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_7b21bcee-b519-4df0-b1d0-30e6a12392b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_7b21bcee-b519-4df0-b1d0-30e6a12392b5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SharebasedCompensationArrangementsbySharebasedPaymentAwardFairValueAssumptionsChangeinWeightedAverageStockPrice_80351df2-311f-427e-ba9d-202e541ad20f" xlink:href="crl-20221231.xsd#crl_SharebasedCompensationArrangementsbySharebasedPaymentAwardFairValueAssumptionsChangeinWeightedAverageStockPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:to="loc_crl_SharebasedCompensationArrangementsbySharebasedPaymentAwardFairValueAssumptionsChangeinWeightedAverageStockPrice_80351df2-311f-427e-ba9d-202e541ad20f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_TradingDayAverageStockPriceOnGrantDate_64a1b5aa-32a5-477d-834f-2dbdf8baf63a" xlink:href="crl-20221231.xsd#crl_TradingDayAverageStockPriceOnGrantDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_c26cbd83-582c-4127-a221-86233bfb8c01" xlink:to="loc_crl_TradingDayAverageStockPriceOnGrantDate_64a1b5aa-32a5-477d-834f-2dbdf8baf63a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c030be50-97db-4b3d-9f42-5c5f7e65ab6b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_169a189f-ca55-4cb5-889a-0d4ac460c321" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c030be50-97db-4b3d-9f42-5c5f7e65ab6b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_7f69f16d-511f-44da-a1bc-642d3c3746b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c030be50-97db-4b3d-9f42-5c5f7e65ab6b" xlink:to="loc_us-gaap_AwardTypeAxis_7f69f16d-511f-44da-a1bc-642d3c3746b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7f69f16d-511f-44da-a1bc-642d3c3746b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_7f69f16d-511f-44da-a1bc-642d3c3746b5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7f69f16d-511f-44da-a1bc-642d3c3746b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_21414311-6415-40b2-8de0-2e6b896c25b8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_7f69f16d-511f-44da-a1bc-642d3c3746b5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_21414311-6415-40b2-8de0-2e6b896c25b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_8a94a56e-28bc-4523-bfb6-02733a0245c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_21414311-6415-40b2-8de0-2e6b896c25b8" xlink:to="loc_us-gaap_PerformanceSharesMember_8a94a56e-28bc-4523-bfb6-02733a0245c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_c5019f89-9ac4-4a53-845b-9cb82383489f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c030be50-97db-4b3d-9f42-5c5f7e65ab6b" xlink:to="loc_srt_TitleOfIndividualAxis_c5019f89-9ac4-4a53-845b-9cb82383489f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_c5019f89-9ac4-4a53-845b-9cb82383489f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_c5019f89-9ac4-4a53-845b-9cb82383489f" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_c5019f89-9ac4-4a53-845b-9cb82383489f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2b0a01a2-21df-4e78-8a14-7cc97bb1ad09" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_c5019f89-9ac4-4a53-845b-9cb82383489f" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2b0a01a2-21df-4e78-8a14-7cc97bb1ad09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_PerformanceSharesGranteeGroupOneMember_d78c9c9b-dc90-4254-9f52-45a6cb77082e" xlink:href="crl-20221231.xsd#crl_PerformanceSharesGranteeGroupOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2b0a01a2-21df-4e78-8a14-7cc97bb1ad09" xlink:to="loc_crl_PerformanceSharesGranteeGroupOneMember_d78c9c9b-dc90-4254-9f52-45a6cb77082e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/RESTRUCTURINGANDASSETIMPAIRMENTSSeveranceandRetentionCostsbyReportableSegmentDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#RESTRUCTURINGANDASSETIMPAIRMENTSSeveranceandRetentionCostsbyReportableSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/RESTRUCTURINGANDASSETIMPAIRMENTSSeveranceandRetentionCostsbyReportableSegmentDetails" xlink:type="extended" id="i63fe5af14a074c789be4a37e97538954_RESTRUCTURINGANDASSETIMPAIRMENTSSeveranceandRetentionCostsbyReportableSegmentDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_07b31261-8f0b-4583-b413-77ec010494be" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_60473509-e765-4933-8ab4-fc22d6e4b8d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_07b31261-8f0b-4583-b413-77ec010494be" xlink:to="loc_us-gaap_RestructuringCharges_60473509-e765-4933-8ab4-fc22d6e4b8d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5fd4efd1-ad55-40a3-b46c-26ac3baff05e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_07b31261-8f0b-4583-b413-77ec010494be" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5fd4efd1-ad55-40a3-b46c-26ac3baff05e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_f1e8a389-e50f-44aa-af9e-b13b30615803" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5fd4efd1-ad55-40a3-b46c-26ac3baff05e" xlink:to="loc_srt_ConsolidationItemsAxis_f1e8a389-e50f-44aa-af9e-b13b30615803" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_f1e8a389-e50f-44aa-af9e-b13b30615803_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_f1e8a389-e50f-44aa-af9e-b13b30615803" xlink:to="loc_srt_ConsolidationItemsDomain_f1e8a389-e50f-44aa-af9e-b13b30615803_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_df9a2da0-9035-4326-b759-3cbe4754dd63" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_f1e8a389-e50f-44aa-af9e-b13b30615803" xlink:to="loc_srt_ConsolidationItemsDomain_df9a2da0-9035-4326-b759-3cbe4754dd63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_9dd2c562-315e-48d1-b5ea-88624abf5c13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_df9a2da0-9035-4326-b759-3cbe4754dd63" xlink:to="loc_us-gaap_CorporateNonSegmentMember_9dd2c562-315e-48d1-b5ea-88624abf5c13" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_2ba22341-70b8-4727-964c-b6235c005501" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5fd4efd1-ad55-40a3-b46c-26ac3baff05e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_2ba22341-70b8-4727-964c-b6235c005501" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_2ba22341-70b8-4727-964c-b6235c005501_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2ba22341-70b8-4727-964c-b6235c005501" xlink:to="loc_us-gaap_SegmentDomain_2ba22341-70b8-4727-964c-b6235c005501_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9e2732d4-67e2-474f-913b-2a69d4bada29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2ba22341-70b8-4727-964c-b6235c005501" xlink:to="loc_us-gaap_SegmentDomain_9e2732d4-67e2-474f-913b-2a69d4bada29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ResearchModelsAndServicesMember_a0f154d0-25ab-42a7-a4e9-8bfd8ddaeeb8" xlink:href="crl-20221231.xsd#crl_ResearchModelsAndServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9e2732d4-67e2-474f-913b-2a69d4bada29" xlink:to="loc_crl_ResearchModelsAndServicesMember_a0f154d0-25ab-42a7-a4e9-8bfd8ddaeeb8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_DiscoveryandSafetyAssessmentMember_a195fd4d-9d39-433f-ae3f-5ce0ec8e33f9" xlink:href="crl-20221231.xsd#crl_DiscoveryandSafetyAssessmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9e2732d4-67e2-474f-913b-2a69d4bada29" xlink:to="loc_crl_DiscoveryandSafetyAssessmentMember_a195fd4d-9d39-433f-ae3f-5ce0ec8e33f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_ManufacturingSupportMember_f4b668e0-5b3b-43b9-b8ad-5ab3daf62665" xlink:href="crl-20221231.xsd#crl_ManufacturingSupportMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9e2732d4-67e2-474f-913b-2a69d4bada29" xlink:to="loc_crl_ManufacturingSupportMember_f4b668e0-5b3b-43b9-b8ad-5ab3daf62665" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/RESTRUCTURINGANDASSETIMPAIRMENTSNarrativeDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#RESTRUCTURINGANDASSETIMPAIRMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/RESTRUCTURINGANDASSETIMPAIRMENTSNarrativeDetails" xlink:type="extended" id="ie86be864edf4493a849997704b8404b9_RESTRUCTURINGANDASSETIMPAIRMENTSNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_7ad8445c-e270-439e-95b1-b880ccabdb47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_47aa49e5-128a-475c-9925-1dddc19aae26" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_7ad8445c-e270-439e-95b1-b880ccabdb47" xlink:to="loc_us-gaap_RestructuringReserve_47aa49e5-128a-475c-9925-1dddc19aae26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_2003a664-fd41-4416-9451-970d38f8e10d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_7ad8445c-e270-439e-95b1-b880ccabdb47" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_2003a664-fd41-4416-9451-970d38f8e10d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_238ba0f1-a5c4-4539-8789-8c973b2cf8ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_2003a664-fd41-4416-9451-970d38f8e10d" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_238ba0f1-a5c4-4539-8789-8c973b2cf8ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_238ba0f1-a5c4-4539-8789-8c973b2cf8ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_238ba0f1-a5c4-4539-8789-8c973b2cf8ad" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_238ba0f1-a5c4-4539-8789-8c973b2cf8ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_79bc270b-7741-44e4-9073-971a013fdb74" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_238ba0f1-a5c4-4539-8789-8c973b2cf8ad" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_79bc270b-7741-44e4-9073-971a013fdb74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_AccruedCompensationMember_581fd00f-f97b-4a8a-8a0a-d46b5d447972" xlink:href="crl-20221231.xsd#crl_AccruedCompensationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_79bc270b-7741-44e4-9073-971a013fdb74" xlink:to="loc_crl_AccruedCompensationMember_581fd00f-f97b-4a8a-8a0a-d46b5d447972" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_8aa1c163-2627-4a0f-b7e7-438238df92d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_2003a664-fd41-4416-9451-970d38f8e10d" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_8aa1c163-2627-4a0f-b7e7-438238df92d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_8aa1c163-2627-4a0f-b7e7-438238df92d9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_8aa1c163-2627-4a0f-b7e7-438238df92d9" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_8aa1c163-2627-4a0f-b7e7-438238df92d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_c933ccb0-2bbe-4af7-8b3b-744608c5a893" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_8aa1c163-2627-4a0f-b7e7-438238df92d9" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_c933ccb0-2bbe-4af7-8b3b-744608c5a893" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_SeveranceAndTransitionCostsMember_4a1e9a66-0acf-44af-a13b-35797ed8f871" xlink:href="crl-20221231.xsd#crl_SeveranceAndTransitionCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_c933ccb0-2bbe-4af7-8b3b-744608c5a893" xlink:to="loc_crl_SeveranceAndTransitionCostsMember_4a1e9a66-0acf-44af-a13b-35797ed8f871" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/LEASESAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#LEASESAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/LEASESAdditionalInformationDetails" xlink:type="extended" id="i68adc87e3f3a413ab8d09fae09c20dce_LEASESAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_38a04951-b170-49bd-b4b0-6d41941e9254" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount_8ced5060-b1ff-493f-82d3-ef2a4128aacf" xlink:href="crl-20221231.xsd#crl_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_38a04951-b170-49bd-b4b0-6d41941e9254" xlink:to="loc_crl_LesseeOperatingLeaseLeaseNotYetCommencedUndiscountedAmount_8ced5060-b1ff-493f-82d3-ef2a4128aacf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_1961ba3e-3c2c-4b80-97c2-b894467f8e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_38a04951-b170-49bd-b4b0-6d41941e9254" xlink:to="loc_us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1_1961ba3e-3c2c-4b80-97c2-b894467f8e5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_c920425e-940d-418b-9cc8-a94284f73ea2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_38a04951-b170-49bd-b4b0-6d41941e9254" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_c920425e-940d-418b-9cc8-a94284f73ea2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_204d0178-067b-450b-abf5-66e920ee49ac" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_c920425e-940d-418b-9cc8-a94284f73ea2" xlink:to="loc_srt_RangeAxis_204d0178-067b-450b-abf5-66e920ee49ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_204d0178-067b-450b-abf5-66e920ee49ac_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_204d0178-067b-450b-abf5-66e920ee49ac" xlink:to="loc_srt_RangeMember_204d0178-067b-450b-abf5-66e920ee49ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dd1d178a-0aa3-480f-a09c-a3719e60d4b1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_204d0178-067b-450b-abf5-66e920ee49ac" xlink:to="loc_srt_RangeMember_dd1d178a-0aa3-480f-a09c-a3719e60d4b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_34f0db56-9078-4b2b-a2e0-5b2cfed188e0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dd1d178a-0aa3-480f-a09c-a3719e60d4b1" xlink:to="loc_srt_MinimumMember_34f0db56-9078-4b2b-a2e0-5b2cfed188e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_41eb4590-9833-46d6-abcb-d639623b53dc" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dd1d178a-0aa3-480f-a09c-a3719e60d4b1" xlink:to="loc_srt_MaximumMember_41eb4590-9833-46d6-abcb-d639623b53dc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.crl.com/role/COMMITMENTSANDCONTINGENCIESAdditionalInformationDetails" xlink:type="simple" xlink:href="crl-20221231.xsd#COMMITMENTSANDCONTINGENCIESAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.crl.com/role/COMMITMENTSANDCONTINGENCIESAdditionalInformationDetails" xlink:type="extended" id="i73e246041c804102beba1e1278033c09_COMMITMENTSANDCONTINGENCIESAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_aa702365-7405-4cdd-8c21-2191f56f715b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_crl_InventoryNonHumanPrimates_f2e47179-dc57-4c30-894d-518f1da3dd2a" xlink:href="crl-20221231.xsd#crl_InventoryNonHumanPrimates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_aa702365-7405-4cdd-8c21-2191f56f715b" xlink:to="loc_crl_InventoryNonHumanPrimates_f2e47179-dc57-4c30-894d-518f1da3dd2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_d00cf4f9-849d-40b1-b6bf-795d872fa5e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_aa702365-7405-4cdd-8c21-2191f56f715b" xlink:to="loc_us-gaap_LossContingenciesTable_d00cf4f9-849d-40b1-b6bf-795d872fa5e6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_aae160b6-300b-47e1-853a-656bbc835fbf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_d00cf4f9-849d-40b1-b6bf-795d872fa5e6" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_aae160b6-300b-47e1-853a-656bbc835fbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_aae160b6-300b-47e1-853a-656bbc835fbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_aae160b6-300b-47e1-853a-656bbc835fbf" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_aae160b6-300b-47e1-853a-656bbc835fbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_f5e7a041-294a-49af-a429-b7b3b2887755" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_aae160b6-300b-47e1-853a-656bbc835fbf" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_f5e7a041-294a-49af-a429-b7b3b2887755" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_77d270bf-3f3f-45ad-b8e0-9c6633a87a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_f5e7a041-294a-49af-a429-b7b3b2887755" xlink:to="loc_us-gaap_SubsequentEventMember_77d270bf-3f3f-45ad-b8e0-9c6633a87a5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_273080d7-2b97-4c8c-a622-dff3e5f00a77" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LitigationStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_d00cf4f9-849d-40b1-b6bf-795d872fa5e6" xlink:to="loc_us-gaap_LitigationStatusAxis_273080d7-2b97-4c8c-a622-dff3e5f00a77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_273080d7-2b97-4c8c-a622-dff3e5f00a77_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_273080d7-2b97-4c8c-a622-dff3e5f00a77" xlink:to="loc_us-gaap_LitigationStatusDomain_273080d7-2b97-4c8c-a622-dff3e5f00a77_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_25849a8f-af3b-46e8-969f-7d4b0bbd0ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_273080d7-2b97-4c8c-a622-dff3e5f00a77" xlink:to="loc_us-gaap_LitigationStatusDomain_25849a8f-af3b-46e8-969f-7d4b0bbd0ec1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PendingLitigationMember_7f17999b-146a-45bd-9054-016b714a57c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PendingLitigationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationStatusDomain_25849a8f-af3b-46e8-969f-7d4b0bbd0ec1" xlink:to="loc_us-gaap_PendingLitigationMember_7f17999b-146a-45bd-9054-016b714a57c1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-roles-2022.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_us-gaap_OtherAssetsNoncurrent" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:type="arc" order="1"/>
  </link:definitionLink>
</link:linkbase>
