Exhibit 99.1

PLACER SIERRA BANCSHARES

PRESS RELEASE

FOR IMMEDIATE RELEASE

For more information contact:

AT THE COMPANY:	AT FINANCIAL RELATIONS BOARD:
Ronald W. Bachli, Chairman & CEO	Tony Rossi
David E. Hooston, Chief Financial Officer	(310) 854-8317
(916) 554-4750

PLACER SIERRA BANCSHARES DECLARES DIVIDEND

FOR SECOND QUARTER OF 2005

Sacramento, Calif., May 20, 2005 — Placer Sierra Bancshares (NASDAQ: PLSB), a $1.8 billion commercial banking company serving the Northern and Southern California markets, announced today that the board of directors declared a quarterly common stock cash dividend of $0.12 per share for the second quarter of 2005. The dividend will be payable on or about June 13, 2005 to shareholders of record on May 31, 2005.

About Placer Sierra Bancshares

Placer Sierra Bancshares is a Northern California-based bank holding company for Placer Sierra Bank with 31 branches in an eight-county area of Northern California, including Placer, Sacramento, El Dorado, Sierra, Nevada, Amador, San Joaquin and Calaveras counties, a loan production office in Fresno County, and nine branches in Southern California’s Orange and Los Angeles counties. Placer Sierra Bank and its divisions, Sacramento Commercial Bank, Bank of Orange County and Bank of Lodi, offer their customers the resources of a large financial institution and the resourcefulness and superior customer service of a community bank.

Placer Sierra Bank offers a broad array of deposit products and services for both commercial and retail customers. These products include electronic banking, cash management services, electronic bill payment and investment services with an emphasis on relationship banking. Placer Sierra Bank also provides competitive loan products such as commercial loans and lines of credit, commercial real estate loans, Small Business Administration loans, residential mortgage loans, home equity lines of credit and construction loans. For more information, please visit www.placersierrabank.com.

Placer Sierra Bancshares is publicly traded on NASDAQ under the stock symbol PLSB. For more information about Placer Sierra Bancshares, please visit www.placersierrabancshares.com.

This press release may contain statements of a forward-looking nature which represent the beliefs of Placer Sierra Bancshares’ management and assumptions concerning future events. Forward-looking statements involve risks, uncertainties and assumptions and are based on information currently available to Placer Sierra Bancshares, which would cause actual results to differ materially from those projected. For a discussion about factors that could cause actual results to differ, please see the publicly available Securities and Exchange Commission filings of Placer Sierra Bancshares. Forward-looking statements are not guarantees of future performance and are to be interpreted only as of the date on which they are made. Placer Sierra Bancshares undertakes no obligation to update any forward-looking statements to reflect events or circumstances that may arise after the date of this release.

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