Sun Microsystems said it is outsourcing its internal information technology team to CSC in a contract worth $US360 million.
Sun said it would save $US100 million over the next five years with the move.
CSC said it would provide software and support for a variety of Sun's internal business activities, such as finance, manufacturing, messaging, enterprise management, customer relations and data warehousing.
The Mercury News reports that some employees at the company will be "badge flipping'' which means they will continue to work at Sun's facilities but will be employed by CSC.
Sun said the moves were part of its overall goal to reduce spending by $US500 million by July 2006.
A report issued by Goldman Sachs said Sun could ultimately contract out up to 45 per cent of its workforce.
Sun said it currently had 32,000 employees worldwide.