Willbros Group Inc (895450) SEC Filing 10-K Annual report for the fiscal year ending Saturday, December 31, 2005

Exhibit 99.1

WILLBROS GROUP, INC.

WILLBROS BRINGS FINANCIAL FILINGS CURRENT AND

REPORTS 2005 AND FIRST QUARTER 2006 RESULTS

HOUSTON, TEXAS – June 16, 2006—Willbros Group, Inc. (NYSE: WG) announced today that it has filed its results for third quarter 2005 on Form 10-Q, for the year ended December 31, 2005 on Form 10-K and for the first quarter 2006 on Form 10-Q. The 2005 and 2006 Forms will be available on the Company’s web site at www.willbros.com. Financial results for the referenced periods are presented as tables to this press release. Willbros also reported that its backlog, adjusted for the sale of the Opal TXP-4 Plant, stood at $820 million at the end of March 2006, as compared to $816 million at December 31, 2005.

“We are moving beyond many of the challenges we have dealt with over the past eighteen months,” stated Michael F. Curran, Chairman and CEO. “After a lot of hard work, we believe we have become a more efficient company, and we are in the process of working through the majority of the remaining legacy work in Nigeria. We continue to see increasing opportunities to expand both our backlog and our revenue at improved contract margins.”

First Quarter 2006

For the quarter ended March 31, 2006, the Company posted operating income of $0.5 million on revenue of $248.5 million. Contract costs were $227.1 million, resulting in a gross margin of 8.6 percent. General and Administrative costs were $15.7 million (or 6.3 percent of revenue). The tax provision was $6.0 million primarily due to taxes payable on a deemed profit basis in Nigeria. Net loss was $(4.6) million, or $(0.22) per share, compared to a net loss of $(9.9) million, or $(0.47) per share, in the first quarter of 2005.

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