Willbros Reports New Project Award

Market Wire, May, 2007

Willbros Group, Inc. (NYSE: WG) today reported that its Construction operations unit, Houston, Texas, was selected for a large diameter pipeline construction project in Texas and Louisiana.

Willbros was awarded a contract by Trunkline Gas Company, a unit of Southern Union Company, to construct two pipelines that are part of Trunkline's Field Zone Expansion Project. One pipeline, a 45-mile 36-inch diameter pipeline along an existing right of way from the Kountze, Texas, compressor station to the Longville, Louisiana, compressor station, gives customers increased access to additional Texas supply. The other pipeline is a 13.5-mile 36-inch diameter pipeline that extends from Kaplan, Louisiana, directly to the Henry Hub. The project is expected to begin in the second quarter of 2007 and is expected to be in service Nov. 1, 2007. Trunkline Gas Company operates a 3,500-mile natural gas pipeline system with access to Gulf Coast supply sources that delivers up to 1.5 billion cubic feet per day of natural gas to Midwest and East Coast markets.

Willbros Group, Inc. is an independent contractor serving the oil, gas and power industries, providing engineering and construction services to industry and government entities worldwide. For more information on Willbros, please visit our web site at www.willbros.com .

This announcement contains forward-looking statements. All statements, other than statements of historical facts, which address activities, events or developments the Company expects or anticipates will or may occur in the future, are forward-looking statements. A number of risks and uncertainties could cause actual results to differ materially from these statements, including those discussed above and such things as the potential for additional investigations; the possible losses arising from the discontinuation of operations and the sale of the Nigeria assets; fines and penalties by government agencies; the outcome of the current Securities and Exchange Commission, Office of Foreign Assets Control and Department of Justice investigations; the identification of one or more other issues that require restatement of one or more prior period financial statements; the existence of material weaknesses in internal controls over financial reporting; availability of quality management; availability and terms of capital; changes in, or the failure to comply with, government regulations; ability to remain in compliance with, or obtain waivers under, the Company's loan agreements and indentures; the promulgation, application, and interpretation of environmental laws and regulations; future E&P capital expenditures, oil, gas, gas liquids and power prices and demand, the amount and location of planned pipelines, the effective tax rate of the different countries where the work is being conducted, development trends of the oil, gas and power industries, changes in the political and economic environment of the countries in which the Company has operations, as well as other risk factors described from time to time in the Company's documents and reports filed with the SEC. The Company assumes no obligation to update publicly such forward-looking statements, whether as a result of new information, future events or otherwise.

CONTACT: Michael W. Collier Vice President, Investor Relations Willbros USA, Inc. (713) 403-8016 Connie Dever Director Strategic Planning Willbros USA, Inc. (713) 403-8035