Exhibit 99.2

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




                                 CERTIFICATION

In connection with the Annual Report of Merck Puerto Rico Employee Savings and
Security Plan (the "Plan") on Form 11-K for the period ended December 31, 2002
as filed with the Securities and Exchange Commission on the date hereof (the
"Report"), I, Caroline Dorsa, Vice President and Treasurer of Merck & Co.,
Inc., certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002, that the Report fully complies
with the requirements of Section 13(a) or 15(d), as applicable, of the
Securities Exchange Act of 1934 and that the information contained in the
Report fairly presents, in all material respects, the financial condition and
results of operations of the Plan.



Dated: June 27, 2003                          /s/ Caroline Dorsa
                                              ----------------------------
                                       Name:  Caroline Dorsa
                                       Title: Vice President and Treasurer


The foregoing certification is being furnished solely pursuant to 18 U.S.C.
Section 1350 and is not being filed as part of the Report or as a separate
disclosure document. A signed original of this written statement required by
Section 906 has been provided to Merck & Co., Inc. and will be retained by
Merck & Co., Inc. and furnished to the Securities and Exchange Commission or
its staff upon request.



                                       13