December 5, 2007

MDA Acquires U.S. - Based Alliance Spacesystems

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today a strategic expansion of its Information Systems business in the United States. The Company has entered into an agreement to acquire privately held Alliance Spacesystems, LLC, located in Pasadena, California.

Alliance Spacesystems provides U.S. Government and aerospace customers with advanced technology solutions, and is a leader in sophisticated robotic and mechanical structures applied on a variety of space missions as well as terrestrial applications.

Mag Iskander, executive vice president and general manager of MDA's Information Systems, stated, "This acquisition significantly enhances our U.S. presence, and will provide a capable conduit to leverage and offer our world class space robotics and space surveillance solutions into the United States civilian and military aerospace markets".

Rene Fradet, CEO of Alliance Spacesystems stated, "We look forward to combining our market access gained through technical excellence with MDA's longstanding experience in the space missions market, to offer our customers a broader range of 'made in the U.S.' solutions".

Alliance Spacesystems will become part of MDA Federal, the MDA subsidiary that includes all of the U.S. businesses of the MDA Information Systems Group. MDA Federal operates under a Special Security Agreement to ensure compliance and optimal access to classified U.S. market opportunities.

The transaction is expected to become accretive within a year. The transaction is expected to close within two weeks subject to required approvals.

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 earth and space based information solutions, ranging from complex operational systems, to tailored information services, to electronic information products.

MDA employs more than 3,000 people in locations across the United States, the United Kingdom, and Canada. The Company's common shares trade on the Toronto Stock Exchange under the symbol. TSX:MDA.

Forward-Looking Statement
This release contains forward-looking statements and information, which reflect the current view of MacDonald, Dettwiler and Associates Ltd. with respect to future events and financial performance. 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. Additional information on these and other potential factors that could affect MDA's financial results are detailed in documents filed from time to time with the applicable Canadian securities regulatory authorities.

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