Ernst Volgenau, founder of SRA International Inc., said yesterday he will step down as chief executive of the company in January but will continue to serve as chairman of the board.

Renato A. DiPentima, who serves as the Fairfax company's president and chief operating officer, will become chief executive.

Volgenau, 71, founded the company in 1978. He has served as chief executive for 26 years and led SRA's growth into a 3,500-employee company that posted a $38.9 million profit on $615.8 million in revenue for the fiscal year ended June 30.

SRA builds communications networks and data-mining tools, integrates and maintains technology infrastructure and offers technical services to government clients. Customers in the homeland security market, including the Department of Defense, accounted for $380.6 million in revenue for the year.

The company raised about $103.5 million in an initial public offering in May 2002.

"This is a great market. The government [information technology] services market has been a great market for more than four years," Volgenau said yesterday, "and it will continue indefinitely in my view."

Volgenau said he is stepping down to spend more time with his family and to teach and write about technology and business. He said he also plans to do more philanthropic work, particularly to help inner-city children. Volgenau said he will stay active in the company and plans to be in the Fairfax office three days a week.

DiPentima, who had been deputy commissioner for systems at the Social Security Administration, joined SRA in 1995. David A. Kriegman, director of SRA's defense sector, will become chief operating officer.

Shares of SRA fell 33 cents yesterday to close at $55.02.