EXHIBIT 99.2

                            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 annual report of McKesson Corporation (the
"Company") on Form 10-K for the year ended March 31, 2003 as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, William
R. Graber, Chief Financial 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 to the best of my knowledge:

(1)      The Report fully complies with the requirements of section 13(a) or
         15(d) of the Securities 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/ William R. Graber
     -------------------------------
     WILLIAM R. GRABER
     Chief Financial Officer
     June 5, 2003

     This certification accompanies the Report pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002, and shall not, except to the extent required by the
Sarbanes-Oxley Act of 2002, be deemed filed by the Company for the purposes of
Section 18 of the Securities Exchange Act of 1934, as amended.

     A signed original of this written statement required by Section 906 has
been provided to McKesson Corporation and will be retained by the Company and
furnished to the Securities and Exchange Commission or its staff upon request.