December 14, 2007

MDA closes Alliance Spacesystems acquisition

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), a provider of essential information solutions, announced today that the Alliance Spacesystems acquisition has closed. The acquisition is expected to be slightly accretive to MDA's earnings in 2008.

With about 128 employees, Alliance Spacesystems currently generates approximately $28 Million USD in annualized revenues. The company is headquartered in Pasadena California, and also has operations in Signal Hill California, and Boulder Colorado. Alliance Spacesystems is a well-positioned U.S. company focused on U.S. civilian defense and commercial space programs.

'This event represents a significant move forward in our effort to access the U.S. civilian and military aerospace markets' stated Daniel Friedmann, president and CEO of MDA. 'MDA has achieved a foothold in early stage U.S. programs including U.S. Space Exploration and surveillance, and in-orbit satellite servicing. By combining MDA with U.S.-domiciled Alliance Spacesystems, MDA is positioned to pursue a much larger share of these future U.S. market opportunities, and can carry out more of the associated work in the U.S.'

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.