Exhibit 99.1





         CERTIFICATION OF PERIODIC FINANCIAL REPORTS


     I, Vincent A. Calarco, Chairman, President and Chief
Executive Officer of Crompton Corporation, 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 Annual Report on Form 10-K for the period
          ended December 31, 2002 (the "Periodic Report")
          which this statement accompanies 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 Periodic Report
          fairly presents, in all material respects, the
          financial condition and results of operations of
          Crompton Corporation.



Date: March 20, 2003

By:/s/Vincent A. Calarco
      Vincent A. Calarco
      Chairman, President and
      Chief Executive Officer