CA said that it will offer $108 per share for the 85 million outstanding shares of the computer services company.
The deal, if completed, would be one of the biggest in the computer industry, on par with Compaq's move to buy Digital for $9.6 billion last month.
It would also place CA in a competitive position against other services companies including IBM, Electronic Data Systems (EDS) and Andersen Consulting.
The $108 price is significantly lower than the $114 the company had reportedly offered CSC in friendly negotiations. CSC apparently rejected this bid, prompting CA to launch its hostile rejoinder. The bid is scheduled to expire March 16.
CSC has undertaken a "poison-pill" shareholder rights plan, designed to ward off hostile bids, but CA said that portions of the poison-pill plan may be inapplicable under Nevada law.
CA has filed plans with the Securities and Exchange Commission outlining the terms of its offer.
CA, the second largest independent software company in the world, has been on a buying spree in the past few years, snapping up Cheyenne Software for $1.2 billion in 1996 and Legent for $1.8 billion in 1995.