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 annual report of Monsanto Company (the "Company") on
Form 10-K for the period ending  December 31, 2002, as filed with the Securities
and Exchange  Commission  on the date hereof (the  "Report"),  I, Frank V. AtLee
III,  Chairman  of the Board,  Chief  Executive  Officer  and  President  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/ Frank V. AtLee III
                                       -----------------------------------------
                                       Frank V. AtLee III
                                       Chairman of the Board, Chief Executive
                                       Officer and President

March 13, 2003