MDA to support U.S. National Security Programs

For immediate release: May 31, 2010

MDA to support U.S. National Security Programs

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today that its U.S. operation, MDA Information Systems, Inc. has been awarded several contracts from confidential customers within the past months, totaling over $7 Million (USD). MDA is building advanced technology solutions in support of U.S. National Security Programs, which are slated to be delivered in 2010 and 2011.

‘MDA takes seriously the trust that our customers have placed in us to provide reliable and quality solutions for programs of such national importance,’ said Ted Cheng, general manager, MDA Information Systems, Inc. ‘The growing depth and breadth of our engineering presence allows us to respond with solutions that will meet the critical needs of our customers.’

About MDA

MDA provides advanced information solutions that capture and process vast amounts of data, produce essential information, and improve the decision making and operational performance of business and government organizations worldwide.

Focused on markets and customers with strong repeat business potential, MDA delivers a broad spectrum of information solutions, ranging from complex operational systems, to tailored information services, to electronic information products.

The Company's common shares trade on the Toronto Stock Exchange under the symbol TSX:MDA.

Related Websites:
www.mdacorporation.com

Forward-Looking Statements

This release contains forward-looking statements and information, which reflect the current view of MacDonald, Dettwiler and Associates Ltd. (“MDA”) with respect to future events and financial performance. The forward-looking statements in this regard include statements regarding the award of a contract. Any such forward-looking statements are based on MDA’s current expectations, estimates, projections and assumptions in light of its experience and its perception of historical trends. Any such forward-looking statements are subject to risks and uncertainties and MDA’s actual results of operations could differ materially from historical results or current expectations. The factors and assumptions underlying the forward-looking statements in this release include contracts not being terminated. MDA cautions readers that should certain risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary significantly from those expected. The risks that could cause actual results to differ from current expectations include failure of third parties and subcontractors; changes in government priorities, funding levels, contracts and regulations; failure of systems to meet performance requirements and failure to anticipate changes in technology, technical standards and product offerings or comply with the requisite standards.

For additional information with respect to certain of these risks or factors, plus additional risks or factors, reference should be made to MDA’s continuous disclosure materials filed from time to time with Canadian securities regulatory authorities, which are available online at www.sedar.com or on MDA’s website at www.mdacorporation.com.

The Toronto Stock Exchange has neither approved nor disapproved the form or content of this release.

For more information, please contact:

Wendy Keyzer
MDA External Relations
Telephone: 604-231-2743
E-mail: wendy@mdacorporation.com