S1 Corporation to Announce Third Quarter 2009 Financial Results On November 5, 2009

NORCROSS, Ga., Oct. 5, 2009 (GLOBE NEWSWIRE) -- S1 Corporation (Nasdaq:SONE), a
leading global provider of customer interaction software solutions for financial
and payment services, announced today that it will release financial results for
the third quarter ended September 30, 2009 on November 5, 2009 after the close
of the financial markets.

The Company will hold an investor conference call on November 6, 2009 at 8:30
a.m. ET hosted by its Chief Executive Officer, Johann Dreyer. The call will be
webcast live for investors and other interested parties, and a replay will be
available two hours after the conference call is complete. To gain access to the
conference call webcast, visit www.s1.com, enter the Investor Relations section,
and click on the webcast icon.

About S1 Corporation

S1 Corporation delivers customer interaction software for financial and payment
services and offers unique solution sets for financial institutions, retailers,
and processors under three brand names: Postilion, S1 Enterprise and FSB
Solutions. Additional information about S1 solutions is available at www.s1.com,
www.postilion.com, www.S1Enterprise.com, and www.fsb-solutions.com.

Forward-Looking Statements

This press release contains forward-looking statements within the safe harbor
provisions of the Private Securities Litigation Reform Act. These statements
include statements with respect to our financial condition, results of
operations and business. The words "believes," "expects," "may," "will,"
"should," "projects," "contemplates," "anticipates," "forecasts," "intends" or
similar terminology identify forward-looking statements. These statements are
based on our beliefs as well as assumptions made using information currently
available to us. Because these statements reflect our current views concerning
future events, they involve risks, uncertainties and assumptions. Therefore,
actual results may differ significantly from the results discussed in the
forward-looking statements. The risk factors included in our reports filed with
the Securities and Exchange Commission (and available on our web site at
http://www.s1.com or the SEC's web site at www.sec.gov) provide examples of
risks, uncertainties and events that may cause our actual results to differ
materially from the expectations we describe in our forward-looking statements.
Except as provided by law, we undertake no obligation to update any
forward-looking statement.

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CONTACT: S1 Corporation
Paul Parrish, Chief Financial Officer
+1 404 923 3500