Chairman & CEO to Make Charitable Donations of ManTech Stock.

FAIRFAX, Va. -- ManTech International Corporation (Nasdaq:MANT), a leading provider of innovative technologies and solutions focused on mission-critical national security programs for the Intelligence Community and the Departments of Defense, State, Homeland Security, and Justice; the Space Community; and other federal government customers, today announced that George J. Pedersen, Chairman and Chief Executive Officer, and his wife, Marilyn A. Pedersen, plan to use ManTech stock to complete donations previously committed to several charitable organizations. These donations will be delivered in late 2006 and early 2007. After the transactions, Mr. Pedersen will retain over 14,500,000 shares of Class B Common Stock.

About ManTech International Corporation:

Headquartered in Fairfax, Virginia, ManTech International Corporation 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 and Justice; the Space Community and other U.S. federal government customers. ManTech's expertise includes systems engineering, systems integration, technology and software development, enterprise security architecture, information assurance, intelligence operations support, network and critical infrastructure protection, information technology, communications integration and engineering support. The company supports the advanced telecommunications systems that are used in Operation Iraqi Freedom and in other parts of the world; provides the physical and cyber security to protect U.S. embassies all over the world; has developed a secure, collaborative communications system for the U.S. Department of Homeland Security; and builds and maintains secure databases that track terrorists. The company operates in the United States and over 40 countries worldwide. In 2005, Red Herring magazine selected ManTech as one of its Small Cap 100 Companies; and in 2006, Business 2.0 magazine named ManTech one of its 100 Fastest Growing Technology Companies. 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. Words such as "may," "will," "intends," "should," "expects," "plans," "projects," "anticipates," "believes," "estimates," "predicts," "potential," "continue," or "opportunity," or the negative of these terms or words of similar import are intended to identify forward-looking statements.

These forward-looking statements are subject to known and unknown risks and uncertainties, which could cause actual results to differ materially from those anticipated, including, without limitation: adverse changes in U.S. government spending priorities; failure to retain existing U.S. government contracts, win new contracts, or win recompetes; uncertainties specifically related to discontinued operations, including our ability to sell or dispose of our MSM operations on terms that are favorable to us, or at all; adverse results of U.S. government audits of our government contracts; adverse effect of contract consolidation; adverse changes in our mix of contract types; risk of contract performance or termination; failure to obtain option awards, task orders or funding under contracts; failure to successfully integrate recently acquired companies or businesses into our operations or to realize any accretive or synergistic effects from such acquisitions; failure to identify, execute or effectively integrate future acquisitions; risks associated with complex U.S. government procurement laws and regulations; and competition. 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 March 10, 2006, and, from time to time, in ManTech's other filings with the Securities and Exchange Commission, including among others, its reports on Form 10-Q.

The forward-looking statements included in this news release are only made as of the date of this news 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.