ManTech International Corporation (NASDAQ: MANT) was awarded a position on the United States Government Omnibus Network Enterprise (USG ONE) vehicle administered by the Department of Defense, Defense Information Systems Agency (DISA). This Indefinite Quantity, Indefinite Delivery (IDIQ) vehicle has a contract ceiling of $476M with a one year base and four one year options. ManTech will provide information and communications support to various federal agencies through this vehicle on a variety of potential task orders.

"We have a strong team in place and look forward to upcoming task orders for this vehicle," said L. William Varner, president and chief operating officer of ManTech's Mission, Cyber and Technology Solutions Group. "ManTech is well positioned to apply our depth and breadth of enterprise solutions to meet our customer's information and communications needs."

About ManTech International Corporation

ManTech is a leading provider of innovative technologies and solutions for mission-critical national security programs for the intelligence community; the departments of Defense, State, Homeland Security, Energy and Justice, including the Federal Bureau of Investigation; the space community; the National Oceanic and Atmospheric Administration; and other U.S. federal government customers. We provide support to critical national security programs through 1,000 current contracts. ManTech's expertise includes command, control, communications, computers, intelligence, surveillance and reconnaissance (C4ISR) lifecycle support, cyber security, global logistics support, intelligence/counter-intelligence support, information technology modernization and sustainment, systems engineering, and test and evaluation. ManTech supports major national missions, such as military readiness, terrorist threat detection, information security and border protection. Additional information on ManTech can be found at www.mantech.com.

Forward-Looking Information

Statements and assumptions made in this press release, which do not address historical facts, constitute "forward-looking" statements that ManTech believes to be within the definition in the Private Securities Litigation Reform Act of 1995 and involve risks and uncertainties, many of which are outside of our control. These forward-looking statements are inherently subject to risks and uncertainties, and actual results and outcomes may differ materially from the results and outcomes we anticipate. Factors that could cause actual results to differ materially from those we anticipate include, but are not limited to, adverse changes in future levels of expenditures for programs we support caused by budgetary pressures facing the federal government and changing mission priorities; the failure to obtain option awards or funding under the contract; risk of contract performance, modification, or termination; the failure to maintain strong relationships with other contractors; and risks associated with complex U.S. government procurement laws and regulations. These and other risk factors are more fully discussed in the section entitled "Risks Factors" in ManTech's Annual Report on Form 10-K, filed with the Securities and Exchange Commission on Feb. 25, 2011, and from time to time in ManTech's other filings. The forward-looking statements included in this news release are only made as of the date of this press release, and ManTech undertakes no obligation to publicly update any of the forward-looking statements made herein, whether as a result of new information, subsequent events or circumstances, changes in expectations or otherwise.

ManTech International Corporation
Lauren Kushin, 703-218-6406
lauren.kushin@mantech.com