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                                                                    Exhibit 99.1

                CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
                      AS ADOPTED PURSUANT TO SECTION 906 OF
                         THE SARBANES-OXLEY ACT OF 2002

          In connection with the Quarterly Report of Waters Corporation (the
"Company") on Form 10-Q for the period ending September 30, 2002 as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Douglas A. Berthiaume, Chairman of the Board of Directors and Chief Executive
Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted
pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that: (1) the Report
fully complies with the requirements of Section 13(a) or 15(d) of the Securities
Exchange Act of 1934; and (2) the information contained in the Report fairly
presents, in all material respects, the financial condition and results of
operations of the Company.

                                       /s/ Douglas A. Berthiaume
                                       -------------------------
                                       Douglas A. Berthiaume
                                       Chairman of the Board of Directors and
                                       Chief Executive Officer


