01.31.05

ULTRA CLEAN TO ANNOUNCE FOURTH QUARTER 2004 RESULTS

MENLO PARK, CA, January 31, 2005 / PRNewswire — Ultra Clean Holdings, Inc. (Nasdaq: UCTT), the parent company of Ultra Clean Technology Systems and Service, Inc., will release fourth quarter and year end 2004 financial results on Tuesday, February 8, 2005 after markets close.

The Company will host a conference call to discuss fourth quarter and year end 2004 financial results and management's outlook at 2:00 pm PDT on Tuesday, February 8, 2005. The call-in number is 800/728-2062 (domestic) and 303/957-1333 (international). A replay of the conference will be available for fourteen days following the call at 800/ 633-8284 (domestic) and 402/ 977-9140 (international). Confirmation number for live broadcast and replay is 21231073 (all callers).

Ultra Clean will also webcast the conference call live on our website at www.uct.com under Investor Relations.

Safe Harbor Statement
The foregoing information contains, or may be deemed to contain, "forward-looking statements" (as defined in the U.S. Private Securities Litigation Reform Act of 1995) which reflect our current views with respect to future events. All forward-looking statements address matters that involve risks and uncertainties. Accordingly, you should not rely on forward-looking statements, as there are or will be important factors that could cause our actual results, as well as those of the markets we serve, levels of activity, performance, achievements and prospects to differ materially from the results predicted or implied by these forward-looking statements. These risks, uncertainties and other factors include, among others, those identified in "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations" and elsewhere in our S-1 registration statement and Form 10-Q's filed with the Securities and Exchange Commission. Ultra Clean Holdings, Inc. undertakes no obligation to publicly update or review any forward-looking statements, whether as a result of new information, future developments or otherwise.