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
ConocoPhillips (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,
J. J. Mulva, President 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.


Date: November 13, 2002


                                     /s/ J. J. Mulva
                            -------------------------------------
                                         J. J. Mulva
                            President and Chief Executive Officer