AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JUNE 23, 2000 REGISTRATION NO. 333- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 -------------------------- FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 -------------------------- CHARLES RIVER LABORATORIES INTERNATIONAL, INC. (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER) DELAWARE 6770 06-139-7316 (STATE OR OTHER (PRIMARY STANDARD (I.R.S. EMPLOYER JURISDICTION INDUSTRIAL IDENTIFICATION NO.) OF INCORPORATION OR CLASSIFICATION CODE ORGANIZATION) NUMBER) 251 BALLARDVALE STREET WILMINGTON, MASSACHUSETTS 01887 (978) 658-6000 (Address, including zip code, and telephone number, including area code, of Registrant's principal executive offices) THOMAS F. ACKERMAN, CHIEF FINANCIAL OFFICER CHARLES RIVER LABORATORIES INTERNATIONAL, INC. 251 BALLARDVALE STREET WILMINGTON, MASSACHUSETTS 01887 (978) 658-6000, EXT. 1225 (978) 694-9504 (FAX) (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF AGENT FOR SERVICE) -------------------------- COPIES TO: MARY E. WEBER, ESQ. RICHARD D. TRUESDELL, JR., ESQ. Ropes & Gray Davis Polk & Wardwell One International Place 450 Lexington Avenue Boston, Massachusetts 02110 New York, New York 10017 (617) 951-7000 (212) 450-4000 (617) 951-7050 (fax) (212) 450-4800 (fax) -------------------------- APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as practicable after this Registration Statement becomes effective. If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. / / If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. /X/ 333-35524 If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. / / If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. / / If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box. / / -------------------------- CALCULATION OF REGISTRATION FEE PROPOSED MAXIMUM PROPOSED MAXIMUM TITLE OF EACH CLASS OF SECURITIES AMOUNT TO BE OFFERING PRICE AGGREGATE AMOUNT OF TO BE REGISTERED REGISTERED PER UNIT(1) OFFERING PRICE(1) REGISTRATION FEE Common Stock, par value $.01 per share........................... 1,725,000 $16.00 $27,600,000 $7,287 (1) Estimated solely for the purpose of computing the amount of the registration fee pursuant to Rule 457(a) under the Securities Act of 1933. - -------------------------------------------------------------------------------- - --------------------------------------------------------------------------------

INCORPORATION BY REFERENCE OF REGISTRATION STATEMENT ON FORM S-1, FILE NO. 333-35524 Charles River Laboratories International, Inc. (the "Company") hereby incorporates by reference into this Registration Statement on Form S-1 in its entirety the Registration Statement on Form S-1 (File No. 333-35524) declared effective on June 23, 2000 by the Securities and Exchange Commission (the "Commission"), including each of the documents filed by the Company with the Commission and incorporated or deemed to be incorporated by reference therein and all exhibits thereto. EXHIBITS The following documents are filed as exhibits to this Registration Statement. EXHIBIT NUMBER DESCRIPTION - ------- ----------- 5.1 Opinion of Ropes & Gray 23.1 Consent of PricewaterhouseCoopers LLP 23.2 Consent of Ropes & Gray (included in Exhibit 5.1)

SIGNATURES Pursuant to the requirements of the Securities Act of 1933, the Registrant has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, State of Massachusetts, on the 23rd day of June, 2000. CHARLES RIVER LABORATORIES INTERNATIONAL, INC. By: /s/ THOMAS F. ACKERMAN --------------------------------------------- Thomas F. Ackerman CHIEF FINANCIAL OFFICER Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities indicated on June 23, 2000. SIGNATURE TITLE --------- ----- * ------------------------------------------- President, Chief Executive Officer (Principal James C. Foster Executive Officer) and Chairman Chief Financial Officer (Principal Financial /s/ THOMAS F. ACKERMAN Officer) and Senior Vice President, Finance ------------------------------------------- and Administration (Principal Accounting Thomas F. Ackerman Officer) * ------------------------------------------- Director Robert Cawthorn * ------------------------------------------- Director Stephen D. Chubb * ------------------------------------------- Director Thompson Dean * ------------------------------------------- Director Stephen C. McCluski * ------------------------------------------- Director Reid S. Perper * ------------------------------------------- Director Douglas E. Rogers II-1

SIGNATURE TITLE --------- ----- * ------------------------------------------- Director Samuel Thier * ------------------------------------------- Director William Waltrip * ------------------------------------------- Director Henry C. Wendt By: /s/ THOMAS F. ACKERMAN -------------------------------------- Attorney-in Fact Thomas F. Ackerman II-2

EXHIBIT INDEX EXHIBIT NUMBER DESCRIPTION - ------- ----------- 5.1 Opinion of Ropes & Gray 23.1 Consent of PricewaterhouseCoopers LLP 23.2 Consent of Ropes & Gray (included in Exhibit 5.1)

EXHIBIT 5.1 [ROPES & GRAY LETTERHEAD] June 23, 2000 Charles River Laboratories International, Inc. 251 Ballardvale Street Wilmington, MA 01887 Re: Charles River Laboratories International, Inc. Ladies and Gentlemen: This opinion is furnished to you in connection with a registration statement on Form S-1 (the "Rule 462(b) Registration Statement"), filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended, for the registration of 1,725,000 shares of Common Stock, $.01 par value (the "Shares"), of Charles River Laboratories International, Inc., a Delaware corporation (the "Company"). The Shares are to be sold pursuant to an underwriting agreement (the "Underwriting Agreement") to be entered into among the Company and Donaldson, Lufkin & Jenrette Securities Corporation, Lehman Brothers Inc., ING Barings LLC, SG Cowen Securities Corporation, U.S. Bancorp Piper Jaffray Inc. and DLJDIRECT Inc., as representatives of the underwriters named therein, together with the shares of Common Stock registered pursuant to a Registration Statement on Form S-1 (File No. 333-35524) of the Company that was declared effective earlier today (the "Initial Registration Statement"). We have acted as counsel for the Company in connection with its proposed issuance and sale of the Shares. For purposes of this opinion, we have examined and relied upon such documents, records, certificates and other instruments as we have deemed necessary. We express no opinion as to the applicability of, compliance with or effect of Federal law or the law of any jurisdiction other than The Commonwealth of Massachusetts and the corporate laws of the State of Delaware. Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, when the Shares have been issued and sold and the Company has received the consideration in accordance with the terms of the Underwriting Agreement, the Shares will be validly issued, fully paid and non-assessable. We hereby consent to your filing this opinion as an exhibit to the Rule 462(b) Registration Statement and to the use of our name therein under the caption "Legal Matters" in the prospectus included in the Initial Registration Statement and incorporated by reference in the Rule 462(b) Registration Statement. It is understood that this opinion is to be used only in connection with the offer and sale of the Shares while the Rule 462(b) Registration Statement is in effect. Very truly yours, /s/ Ropes & Gray ---------------------------- Ropes & Gray

EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in this Registration Statement of our report dated March 29, 2000, except as to the exchange of shares which is as of June 21, 2000, relating to the consolidated financial statements of Charles River Laboratories International, Inc., as of December 25, 1999 and December 26, 1998 and for each of the three years in the period ended December 25, 1999, which appear in Charles River Laboratories International, Inc.'s Registration Statement on Form S-1 (File No. 333-35524). PricewaterhouseCoopers LLP June 23, 2000