SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Form 11-K

(x)   ANNUAL REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2001

OR

( )   TRANSITION REPORT PURSUANT TO SECTION 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                 to                  

Commission file number 0-12508

A.  Full title of the plan and the address of the plan, if different from that of the issuer named below:

S&T BANCORP, INC., THRIFT PLAN FOR EMPLOYEES OF S&T BANK

B.  Name of issuer of the securities held pursuant to the plan and the address of its principle executive office:

S&T BANCORP, INC.
43 SOUTH NINTH STREET
INDIANA, PA 15701

Thrift and Retirement Plan Committee

S&T Bank

We have audited the accompanying statements of net assets available for benefits of the Thrift Plan for Employees of S&T Bank as of December 31, 2001 and 2000, and the related statements of changes in net assets available for benefits for the years then ended. These financial statements are the responsibility of the Plan's management. Our responsibility is to express an opinion on these financial statements based on our audits.

We conducted our audits in accordance with auditing standards generally accepted in the United States. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the Plan at December 31, 2001 and 2000, and the changes in its net assets available for benefits for the years then ended, in conformity with accounting principles generally accepted in the United States.

Our audits were performed for the purpose of forming an opinion on the financial statements taken as a whole. The accompanying supplemental schedule of assets held at end of year as of December 31, 2001 is presented for purposes of additional analysis and is not a required part of the financial statements, but is supplementary information required by the Department of Labor's Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. This supplemental schedule is the responsibility of the Plan's management. The supplemental schedule has been subjected to the auditing procedures applied in our audit of the financial statements and, in our opinion, is fairly stated in all material respects in relation to the financial statements taken as a whole.

June 21, 2002

A description of significant accounting policies of the Thrift Plan for Employees of S&T Bank (the Plan) is presented below.

The financial statements have been prepared on the accrual basis of accounting.

The investment assets are held in trust with the Wealth Management Department of S&T Bank (the Trustee).

Investments are stated at estimated fair value. Securities traded on a national securities exchange are valued at the last reported sales price on the last business day of the plan year; investments traded in the over-the-counter market and listed securities for which no sale was reported on that date are valued at the average of the last reported bid and asked prices. Short-term investment funds and mutual funds are valued based on quoted market prices as of the end of the plan year.

Realized gains and losses from investment transactions are computed principally using the first-in, first-out (FIFO) method.

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

The Plan was adopted effective May 1, 1984 and made retroactive to January 1, 1984 by S&T Bank (Plan Sponsor and Employer).

The Plan is a vehicle for accepting employee and Employer tax-deferred contributions and employee after-tax contributions. Eligible employees (participants) determine the amount of their deferred cash contributions to the Plan. Employer matching contributions are equal to 50% of the employee contributions, not to exceed 3% of compensation. Employer discretionary contributions are determined by the Board of Directors of the Plan Sponsor.

The Plan was amended, effective December 30, 1988, to include an Employee Stock Ownership Plan (ESOP). The ESOP covers substantially all regular employees under the Plan. ESOP contributions are invested primarily in qualified securities (common stock) of S&T Bancorp, Inc. (Bancorp), the parent company of the Plan Sponsor. At December 31, 2001 and 2000, there were no unreleased shares from the Plan.

Effective October 1, 1998, the Plan was amended and restated to permit eligible employees to participate in the Plan upon employment with Bancorp. The Plan was also amended to include automatic participation of eligible participants unless participants elect otherwise. The Plan was also amended to comply with the Small Business Job Protections Act of 1996 and the Taxpayer Relief Act of 1997. A favorable determination letter was received on August 4, 1999.

Effective January 1, 2001, the Plan was amended and restated in its entirety to incorporate revisions of applicable federal regulation. In addition, the restatement revised the hardship distribution rules. A determination letter request was submitted on February 28, 2002.

Individual accounts are maintained for each participant. Participants may elect to invest their contributions in one or more of various investment options. Employer matching contributions are invested in the same proportions. The Employer discretionary contributions are made at the direction of the Thrift and Retirement Plan Committee of the Plan Sponsor. Participants are permitted to transfer all balances in their accounts between investment options.

Each participant's account is credited with the participant's contributions, Employer matching contributions and allocations of other Employer contributions and fund earnings, which are allocated based on the participant's compensation and the participant's fund balances, respectively. The benefit to which a participant is entitled is the amount aggregated in the participant's account. Aggregate participant account balances differ from net assets available for benefits only by routine accruals.

Participants are immediately vested in all amounts credited to their accounts. On termination of service, participants may elect either to receive a lump-sum distribution from their accounts, or to leave their funds in the Plan, provided their balance is at least $5,000.

At December 31, 2001 and 2000, benefit payments in the amount of $103,047 and $313,755, respectively, were owed to participants who had elected to withdraw from the Plan, but had not yet been paid.

The Plan Sponsor reserves the right to amend or discontinue the Plan. In the event of a termination of the Plan, plan assets would be used for the benefit of participants and their beneficiaries, as prescribed by law.

For more complete information about the Plan including participation, vesting, and benefit provisions, refer to the Summary Plan Description, which can be obtained from the Plan Sponsor.

During 2001 and 2000, the Plan's investments (including investments purchased and sold, as well as held during the year) appreciated (depreciated) in fair value by $2,049,227 and ($2,604,792), respectively, as follows:

The fair value of individual investments that represent 5% or more of the Plan's net assets available for plan benefits is as follows:

All investment information disclosed in the financial statements and supplemental schedule, including investments held at December 31, 2001 and 2000, and net appreciation (depreciation) in fair value of investments, interest, and dividends for the years ended December 31, 2001 and 2000, were obtained or derived from information supplied to the plan administrator and certified as complete and accurate by the Trustee.

Legal, accounting, and other administrative fees are paid by the Plan Sponsor. The Plan is administered by the Plan Sponsor, and the Wealth Management Department of S&T Bank acts as trustee and safekeeping agent.

At December 31, 2001 and 2000, respectively, the Plan held an aggregate of 941,138 and 969,234 shares of S&T Bancorp, Inc. common stock valued at $22,850,831 and $20,959,685.

The Plan has received a determination letter from the Internal Revenue Service dated August 4, 1999, stating that the Plan is qualified under Section 401(a) of the Internal Revenue Code (the Code) and, therefore, the related trust is exempt from taxation. Once qualified, the Plan is required to operate in conformity with the Code to maintain its qualification. The Plan Sponsor believes the Plan is being operated in compliance with the applicable requirements of the Code and, therefore, believes that the Plan is qualified, and the related trust is tax-exempt.

*Indicates party-in-interest to the Plan