Most Recently Chief Operating Officer of Science Applications International Corporation (SAIC)

ManTech International Corporation (Nasdaq:MANT) announced today that Lawrence B. Prior III has been selected as the Company’s President and Chief Operating Officer and will begin his new role in early July 2009. Mr. Prior will also become a member of ManTech’s Board of Directors. Mr. Prior is joining ManTech from SAIC where he had been the Chief Operating Officer since October 2007.

“I am very pleased to welcome Larry to the ManTech team as his extensive experience will be critical in helping us achieve our next stage growth goals over the next several years,” said George J. Pedersen, Chief Executive Officer and Chairman of the Board, ManTech International Corporation. “Larry brings exceptional attributes to the position and will be a key partner with me and our Board of Directors in making ManTech the premier mid-tier national security firm in the marketplace.”

Mr. Barry Campbell, ManTech’s Presiding Independent Director, also expressed his pleasure with Mr. Prior’s decision to join the ManTech management team and become a member of the Board of Directors, stating “the Board considers Larry to be uniquely qualified for this position at this critical time in ManTech’s history.”

"I am honored to accept the position and excited to continue ManTech’s exceptional track record over its 40-year history," said Lawrence B. Prior III, President and Chief Operating Officer, ManTech International Corporation. "I was drawn to the Company’s mission critical support of US national security: ManTech’s Cyber capability leads the market and George’s leadership coupled with the Board’s commitment to our deployed customers from State, Defense and Intelligence is extraordinary and positions the Company well to support the growing US strategy of Smart Power and Threat Reduction. ManTech is a unique company that is exceptionally well-positioned to deliver advanced technology solutions to a wide variety of important customers in the Defense, Intelligence, Homeland Security & Law Enforcement, State Department, Space Community and other key government markets. I look forward to working with this very talented technical team.”

Before his selection as Chief Operating Officer of SAIC in 2007, Mr. Prior was the President of SAIC’s Intelligence, Security & Technology Group from 2004 until 2007. Before joining SAIC, Mr. Prior was the CEO and CFO of LightPointe Communications. He was also previously the Chief Administrative Officer for the County of San Diego and an executive at TRW. Mr.