SI International Wins Air Force Space Command Contract

SI International to Provide Space Sensors System Engineering and Technical Services

SI International, Inc.
announced today that it has been awarded a contract to provide
space sensors engineering and technical services support to the Air Force
Space Command (AFSPC). The competitive task order contract has a one-year
base period with eight one-year options. The contract’s potential value is
$43.5 million over nine years, if all options are exercised.

“With a strong background in space systems modernization, we look forward
to the ongoing opportunities to support the Air Force Space Command in their
mission-critical work,” said Ray Oleson, Chairman and CEO of SI International.

With space systems modernization as a key focus area, SI International has
been supporting the North American Aerospace Defense Command (NORAD), United
States Space Command (USSPACECOM) — now United States Strategic Command
(USSTRATCOM), and Air Force Space Command (AFSPC) for more than eight years.
In addition, SI International has supported the Spacelift Range Systems, Range
Standardization and Automation, military satellite communication (Milsatcom)
systems, the Air Force Satellite Control Network, and other AFSPC programs
since 1996.

About SI International: SI International is a provider of information
technology and network solutions primarily to the federal government. The
company combines technological and industry expertise to provide a full
spectrum of state-of-the-practice solutions and services, from design and
development to documentation and operations, to assist clients in achieving
their missions. More information about SI International can be found at
www.si-intl.com.

This press release contains various remarks about the future expectations,
plans and prospects of SI International, Inc. that constitute forward-looking
statements for purposes of the safe harbor provisions under The Private
Securities Litigation Reform Act of 1995. The actual results of SI
International, Inc. may differ materially from those indicated by these
forward-looking statements as a result of various important factors, including
those discussed in the Risk Factors section of the registration statement on
Form S-1 filed by SI International, Inc. with the Securities and Exchange
Commission and available directly from the Commission at www.sec.gov.