MDA'S Second Quarter 2005 Results Conference Call Alert

Richmond, B.C. - MacDonald, Dettwiler and Associates Ltd. (TSX: MDA), plans to release Second Quarter 2005 financial results at close of market on Thursday, July 28th.

MDA will host an earnings conference call, featuring remarks by President and CEO Daniel Friedmann, and Anil Wirasekara, Executive Vice-President and CFO, followed by a Q & A session.

The call is scheduled to begin promptly at 4:30PM Eastern Time, (1:30PM Pacific Time).

To participate, please call the conference line approximately five minutes prior to the commencement of the call:

About MacDonald, Dettwiler and Associates Ltd. (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 2,500 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.

Related Websites:
www.mdacorporation.com