Willbros 10-Q 2011 Q2 Quarterly report

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 June 30, 2011 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Robert R. Harl 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: August 1, 2011	/s/ Robert R. Harl
	Robert R. Harl
	Chief Executive Officer