The three year $8m contract has three two year extension options potentially providing a nine year deal.
"This contract with CASA reaffirms ASG's unique position as the leading Australian IT Managed Services provider and clearly differentiates us in our chosen markets," said Murray Rosa chief officer sales & strategic operations ASG.
"This is another multi-year contract for ASG that provides a significant boost to our revenue in the 2009 financial year and beyond.
"We are in advanced discussions on other significant contracts and feel well placed to secure additional work in the coming months."
CASA is the Federal agency responsible for ensuring the safety regulation of civil air operations in Australia and the operation of Australian aircraft overseas.
It provides safety education and training programs.
The contract follows other Federal Government projects recently secured by ASG with the National Museum of Australia, National Capital Authority, IP Australia, Department of the Prime Minister and Cabinet and Airservices Australia.
Rosa said the company's Federal Region operation in Canberra had demonstrated strong growth during the 2009 financial year.