2008-10-07 18:27:03 -

www.tetratech.com - Tetra Tech, Inc. (NASDAQ:TTEK) announced today that it is one of five contractors that has been awarded a $500 million global architect-engineer infrastructure services contract with the U.S. Agency for International Development (USAID). The contractors will share in the $500 million award ceiling for this five-year indefinite-delivery, indefinite-quantity contract.

Tetra Tech will provide

engineering studies and design services for USAID funded infrastructure projects worldwide, including water resources, civil infrastructure, telecommunications, and power generation projects. Support could range from emergency response to multi-year projects. Much of the work will be performed in areas that have been impacted by disaster or conflict.

"Tetra Tech is honored to have been selected for this important USAID contract," said Dan Batrack, Tetra Tech's Chairman and CEO. "Tetra Tech is combining its international development experience and its expertise in engineering and infrastructure development to provide innovative solutions that improve the quality of life in the developing world."

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering, and technical services. With approximately 8,500 associates located in the United States and internationally, the Company supports commercial and government clients in the areas of resource management and infrastructure. Tetra Tech's services include research and development, applied science and technology, engineering design, program management, construction management, construction, and operations and maintenance.

Any statements made in this release that are not based on historical fact are forward-looking statements. Any forward-looking statements made in this release represent management's best judgment as to what may occur in the future. However, Tetra Tech's actual outcome and results are not guaranteed and are subject to certain risks, uncertainties and assumptions ("Future Factors"), and may differ materially from what is expressed. For a description of Future Factors that could cause actual results to differ materially from such forward-looking statements, see the discussion under the section "Risk Factors" included in the Company's Form 10-K and 10-Q filings with the Securities and Exchange Commission.

Tetra Tech, Inc.
Jorge Casado, Investor Relations
Talia Starkey, Media & Public Relations
626-351-4664