The two firms say the takeover will boost both companies
Computer giant Dell is buying IT services provider and fellow Texan firm Perot Systems for $3.9bn (£2.4bn).
Dell said the takeover, which it hopes to conclude between November and January, will help it provide a wider range of services to its customers.
The all-cash deal will see Perot shareholders receive $30 per share, a 68% premium on the company's closing share price on Friday.
Perot is controlled by billionaire Ross Perot who twice ran for US president.
He ran as an independent candidate in both 1992 and 1996.
"We consider Perot Systems to be a premium asset with great people that enhances our opportunities for immediate and long-term growth," said Dell's chairman and chief executive.
"This significantly expands Dell's enterprise-solutions capabilities and makes Perot Systems' strengths available to even more customers around the world," Michael Dell added.
While Perot specialises in IT support for the likes of hospitals, government departments, and banks, Dell is best known for its personal computers.
Mr Perot said the sale was a "great opportunity" for his company, which he founded in 1988.
Mr Dell said the "the acquisition makes such great sense because of the obvious ways our businesses complement each other".
The takeover news comes a month after Dell reported that its second quarter revenues fell 22% from a year earlier to $12.8bn, as it continued to be hit by the global slowdown in sales of personal computers.