EXHIBIT 32.1

                            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 Willbros Group, Inc. (the
"Company") on Form 10-Q for the quarter ended September 30, 2004 as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Michael F. Curran, Chief Executive Officer of the Company, hereby 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 9, 2004                     /s/ Michael F. Curran
                                           ----------------------------------
                                           Michael F. Curran
                                           Chief Executive Officer

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