BAE Systems has signed a new $1.9bn (£1.1bn) outsourcing deal with CSC.
The five-year contract replaces an existing agreement that was due to expire this October.
Under the new agreement CSC will continue to manage IT operations for a number of units at the defence and aerospace company.
The services that CSC is responsible for include the management of mainframe and midrange computers, servers and desktops, the provision of local and wide area networking, helpdesk support, application development, and procurement services.
BAE Systems programme director Steve Barrett said, “Since 1994, BAE Systems and CSC have worked together to respond to technology changes in the IT arena.
"This new next-generation outsourcing contract delivers flexibility, improved service and savings to BAE Systems businesses."
The relationship between the companies began in 1994 with a 10-year $1.5bn IT outsourcing contract in the UK.
Under the existing agreement, CSC provides IT services to 13 BAE Systems businesses and joint ventures operating across 120 locations in the UK and North America.