EXHIBIT 31.1

                            CERTIFICATION PURSUANT TO

                  SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

            AND RULE 13a-14(a)/15d-14(a) OF THE EXCHANGE ACT OF 1934

     I, James C. Foster, Chief Executive Officer of Charles River Laboratories
International, Inc. (the Company) certify that:

     1. I have reviewed this annual report on Form 10-K of the Company;

     2. Based on my knowledge, this annual report does not contain any untrue
        statement of a material fact or omit to state a material fact necessary
        to make the statements made, in light of the circumstances under which
        such statements were made, not misleading with respect to the period
        covered by this annual report;

     3. Based on my knowledge, the financial statements, and other financial
        information included in this annual report, fairly present in all
        material respects the financial condition, results of operations and
        cash flows of the registrant as of, and for, the periods presented in
        this annual report:

     4. The registrant's other certifying officers and I are responsible for
        establishing and maintaining disclosure controls and procedures (as
        defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the
        registrant and have:

        a. designed such disclosure controls and procedures, or caused such
           disclosure controls and proceeds to be designed under our new
           supervision, to ensure that material information relating to the
           registrant, including its consolidated subsidiaries, is made known to
           us by others within those entities, particularly during the period in
           which this annual report is being prepared;

        b. [Paragraph omitted pursuant to Sec Release Nos. 33-8238 and
           34-47986];

        c. evaluated the effectiveness of the registrant's disclosure controls
           and procedures and presented in this report our conclusions about the
           effectiveness of the disclosure controls and procedures as of the end
           of the period covered by this report based on such evaluation; and

        d. Disclosed in this report any change in the registrant's internal
           control over financial reporting that occurred during the
           registrant's most recent fiscal quarter (the registrant's fourth
           fiscal quarter in the case of an annual report) that has materially





           affected, or is reasonably likely to materially affect, the
           registrant's internal control over financial reporting; and;

        5. The registrant's other certifying officers and I have disclosed,
           based on our most recent evaluation of internal control over
           financial reporting, to the registrant's auditors and the audit
           committee of registrant's board of directors (or persons performing
           the equivalent functions):

           a. all significant deficiencies and material weaknesses in the design
              or operation of internal control over financial reporting which
              are reasonably likely to adversely affect the registrant's ability
              to record, process, summarize and report financial information;
              and

           b. any fraud, whether or not material, that involves management or
              other employees who have a significant role in the registrant's
              internal control over financial reporting.


                               /s/ James C. Foster
                               ----------------------------------------------
                               James C. Foster
                               Chairman, Chief Executive Officer and President
Dated: March 8, 2004           Charles River Laboratories International, Inc.