EXHIBIT 32.2

                            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 quarterly report of Willbros Group, Inc. (the
"Company") on Form 10-Q for the quarter ended June 30, 2004 as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), I, Warren
L. Williams, Chief Financial 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: August 9, 2004                            /s/ Warren L. Williams
                                                --------------------------------
                                                Warren L. Williams
                                                Chief Financial Officer