UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              --------------------

                                    FORM 8-K

                                 CURRENT REPORT
                     Pursuant to Section 13 OR 15 (d) of the
                         Securities Exchange Act of 1934

                                September 8, 2005
                Date of Report (Date of earliest event reported)


                 CHARLES RIVER LABORATORIES INTERNATIONAL, INC.
             (Exact Name of Registrant as specified in its Charter)

                              --------------------


           Delaware                 333-92383                 06-1397316
 (State or Other Jurisdiction)     (Commission             (I.R.S. Employer
       of Incorporation            File Number)           Identification No.)

                              --------------------

                       251 Ballardvale Street
                      Wilmington, Massachusetts            01887
             (Address of Principal Executive Offices)    (Zip Code)


                                  978-658-6000
              (Registrant's Telephone Number, including Area Code)



ITEM 7.01. Regulation FD Disclosure The following information shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. On September 8, 2005, Charles River Laboratories International, Inc. issued a press release updating the third-quarter 2005 outlook. The press release, attached as an exhibit to this report, includes "safe harbor" language pursuant to the Private Securities Litigation Reform Act of 1995, as amended, indicating that certain statements contained in the press release are "forward-looking" rather than historic. The press release also states that these and other risks relating to Charles River are set forth in the documents filed by Charles River with the Securities and Exchange Commission. ITEM 9.01. Financial Statements and Exhibits (a) Not applicable. (b) Not applicable. (c) Exhibits. 99.1 Press release dated September 8, 2005. 2

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. CHARLES RIVER LABORATORIES INTERNATIONAL, INC. Dated: September 8, 2005 By: /s/ Jody Acford --------------------------------- Jody Acford, Corporate Senior Vice President, General Counsel and Corporate Secretary 3

Exhibit Index Exhibit No. Description - ----------- ----------- 99.1 Press release dated September 8, 2005. 4

                                                                    Exhibit 99.1

 Charles River Laboratories Updates Outlook for Third Quarter of 2005

    WILMINGTON, Mass.--(BUSINESS WIRE)--Sept. 8, 2005--Charles River
Laboratories International, Inc. (NYSE:CRL) today said that based upon
its current forecast, it expects that for the third quarter ending
September 24, 2005, at current exchange rates, its net sales growth
and earnings per diluted share will be at the low end, or slightly
below, its previous guidance. The Company had stated that it expected
net sales growth to be in a range of 58-61%, earnings per diluted
share in a range of $0.44 to $0.46, and non-GAAP earnings per diluted
share in a range of $0.58 to $0.60. Non-GAAP guidance excludes
acquisition-related amortization of intangibles of $13.1 million and
compensation charges of $1.3 million. The Company will provide updated
guidance for full-year 2005 when it reports third-quarter earnings on
October 27, 2005, once September and third-quarter results have been
finalized.
    James C. Foster, Chairman, President and Chief Executive Officer
said, "Our updated guidance for the third quarter reflects continued
softness in demand for Transgenic Services in the United States,
increased seasonality in the research models business, particularly in
Europe, several preclinical study delays and continued weakness in
Interventional and Surgical Services. We are evaluating initiatives to
improve operations in some of these businesses."
    Mr. Foster added, "We are pleased that our integration of Inveresk
has proceeded on schedule and right in line with our expectations. In
addition, our preclinical toxicology business is performing well and
our clinical business continues to improve. From a long-term
perspective, we continue to see our business strongly positioned as a
leading provider to the pharmaceutical and biotechnology industries.
Our portfolio of businesses provides pharmaceutical and biotechnology
companies the products and services which are essential to their drug
discovery and development effort."
    The Company will discuss this press release during its
presentation at the Thomas Weisel Healthcare Tailwinds Conference in
Boston on Thursday, September 8, at 9:45 a.m. ET. A live webcast of
the Company's presentation will be available at ir.criver.com. The
webcast replay will be available approximately two hours after the
presentation and will remain available until September 15, 2005.

    Use of Non-GAAP Financial Measures

    This press release contains non-GAAP financial measures which
exclude, among other items, amortization of intangible assets and
other charges related to the Inveresk acquisition. We exclude these
items from the non-GAAP financial measures because they are outside
our normal operations. We believe that the inclusion of non-GAAP
financial measures in this press release helps investors to gain a
meaningful understanding of our core operating results and future
prospects, and is consistent with how management measures and
forecasts the Company's performance, especially when comparing such
results to prior periods or forecasts. Non-GAAP results also allow
investors to compare the Company's operations against the financial
results of other companies in the industry who similarly provide
non-GAAP results. The non-GAAP financial measures included in this
press release are not meant to be considered superior to or a
substitute for results of operations prepared in accordance with GAAP.
Reconciliations of the non-GAAP financial measures used in this press
release to the most directly comparable GAAP financial measures are
set forth in the text of, and the accompanying exhibits to, this press
release, and can also be found on the Company's website at
ir.criver.com.

    Caution Concerning Forward-Looking Statements. This news release
includes forward-looking statements within the meaning of the Private
Securities Litigation Reform Act of 1995. Forward-looking statements
may be identified by the use of words such as "anticipate," "believe,"
"expect," "estimate," "plan," "outlook," and "project" and other
similar expressions that predict or indicate future events or trends
or that are not statements of historical matters. Forward-looking
statements are based on Charles River's current expectations and
beliefs, and involve a number of risks and uncertainties that could
cause actual results to differ materially from those stated or implied
by the forward-looking statements. Those risks and uncertainties
include, but are not limited to: challenges arising from the
acquisition and integration of Inveresk Research Group; a decrease in
research and development spending or a decrease in the level of
outsourced services; acquisition integration risks; the ability to
convert backlog to sales; special interest groups; contaminations;
industry trends; new displacement technologies; USDA and FDA
regulations; changes in law; continued availability of products and
supplies; loss of key personnel; interest rate and foreign currency
exchange rate fluctuations; changes in tax regulation and laws;
changes in generally accepted accounting principles; and any changes
in business, political, or economic conditions due to the threat of
future terrorist activity in the U.S. and other parts of the world,
and related U.S. military action overseas. A further description of
these risks, uncertainties, and other matters can be found in the Risk
Factors detailed in Charles River's Annual Report on Form 10-K as
filed on March 9, 2005, with the Securities and Exchange Commission.
Because forward-looking statements involve risks and uncertainties,
actual results and events may differ materially from results and
events currently expected by Charles River, and Charles River assumes
no obligation and expressly disclaims any duty to update information
contained in this news release except as required by law.

    About Charles River Laboratories

    Charles River Laboratories, based in Wilmington, Massachusetts, is
a global provider of solutions that advance the drug discovery and
development process. Our leading-edge products and services are
designed to enable our clients to bring drugs to market faster and
more efficiently. Backed by our rigorous, best-in-class procedures and
our proven data collection, analysis and reporting capabilities, our
products and services are organized into three categories spanning
every step of the drug development pipeline: Research Models and
Services, Preclinical Services, and Clinical Services. Charles River's
customer base includes all of the major pharmaceutical companies and
many biotechnology companies, government agencies and leading
hospitals and academic institutions. Charles River's 8,000 employees
serve clients in more than 50 countries. For more information on
Charles River, visit our website at www.criver.com.

    CONTACT: Charles River Laboratories International, Inc.
             Susan E. Hardy, 978-658-6000 Ext. 1616
             Director, Investor Relations