Contact: Susan Tomera Angeletti

724-465-4870

TO BE RELEASED

9:00 a.m., Tuesday, December 20, 2005

S&T Bancorp, Inc. Declares Quarterly Cash Dividend

and Approves Repurchase Authorization

Indiana, Pennsylvania - S&T Bancorp, Inc. (NASDAQ NMS: STBA) announced that its Board of Directors declared a $0.29 per share cash dividend payable on January 25, 2006 to shareholders of record on December 30, 2005. This represents a 7.0 percent increase over the dividend declared in December 2004 and a3.0 percent annualized yield utilizing the December 19, 2005 closing stock price of $37.63. The Board of Directors also approved a share repurchase authorization of up to one million shares or approximately 4.0 percent of shares outstanding through year-end 2006.

Headquartered in Indiana, PA, S&T Bank, the principal subsidiary of S&T Bancorp, Inc., operates 50 offices within Allegheny, Armstrong, Blair, Butler, Cambria, Clarion, Clearfield, Indiana, Jefferson and Westmoreland counties. With assets of $3.2 billion, S&T Bancorp, Inc. stock trades on the NASDAQ National Market System under the symbol STBA.

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