Tetra Tech, Inc. (NASDAQ:TTEK) announced today that Dan Batrack, Chairman and Chief Executive Officer, and Jorge Casado, Vice President of Investor Relations, will give a presentation to investors at the Eighth Annual D.A. Davidson Engineering & Construction Conference in San Francisco, California on Thursday, September 17, 2009, at 8:30 a.m. Pacific Time. Tetra Tech invites investors and other interested parties to attend a live webcast of its presentation. The webcast and a copy of the presentation slides will be available on the Company’s website at www.tetratech.com. A replay of the presentation will be available on the website following the presentation.

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering, program management, construction, and technical services addressing the resource management and infrastructure markets. The Company supports government and commercial clients by providing innovative solutions focused on water, the environment, and energy. With more than 10,000 employees worldwide, Tetra Tech’s capabilities span the entire project life cycle.

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.