Tetra Tech Announces Planned Dates for First Quarter 2005 Results and

    Business Editors

    PASADENA, Calif.--(BUSINESS WIRE)--Jan. 7, 2005--Tetra Tech, Inc. (NASDAQ: TTEK) today announced the planned dates for its first quarter 2005 results and conference call. On Wednesday, January 26, 2005, after market close, Tetra Tech intends to announce its first quarter 2005 results. On Thursday, January 27, 2005, at 8:00 a.m. Pacific Time, Tetra Tech plans to host a conference call to further present and discuss the Company's financial results.
    Investors can access a live audio-visual webcast through a link posted on the Company's website at www.tetratech.com. The webcast will be available for replay through April 27, 2005.

    About Tetra Tech (www.tetratech.com)

    Tetra Tech is a leading provider of consulting, engineering and technical services. With over 8,000 associates located in the United States and internationally, the Company supports commercial and government clients in the areas of resource management, infrastructure and communications. Tetra Tech's services include research and development, applied science and technology, engineering design, program management, construction management, 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.

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CONTACT: Tetra Tech, Inc. Li-San Hwang or Mike Bieber, 626-351-4664

KEYWORD: CALIFORNIA INDUSTRY KEYWORD: ENVIRONMENT TELECOMMUNICATIONS REAL ESTATE BUILDING/CONSTRUCTION MANUFACTURING ADVISORY CONFERENCE CALLS SOURCE: Tetra Tech, Inc.

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