Jack D. Little, 52, a computer consultant and a former president of the Planning Research Corp. here, died Saturday at Beebe Hospital in Lewes, Del., following a heart attack. He was stricken in Bethany Beach, Del., where he was on vacation.

Mr. Little, who lived in Potomac, was president of Planning Research Corp. -- a computer-services, management consulting and engineering firm -- from 1977, when the company moved its headquarters from Los Angeles to Washington, until last year. He had joined the firm in 1962. He was an independent consultant at the time of his death.

A native of Madison, Ill., Mr. Little served in the Navy from 1946-48. He then went to Westminster College in Salt Lake City and graduated with a bachelor's degree in mathematics and education. After college, he moved to California and went to work for the Sperry Corp.

In 1954, he joined the Rand Corp. in Los Angeles. He was head of the computer team supporting its economics, logistics and cost-effectiveness departments. He also taught computer programming at Santa Monica City College and was a private consultant. In 1962, he joined Planning Research Corp.

In 1979, Mr. Little completed the graduate advanced-management program at the Harvard Business School.

He was a member of the American Managmenet Association and the Harvard Business School Club.

Survivors include his wife Lydia of Potomac; two daughters, Susan Orban Of Damascus, Md., and Kimberly Daley of Flagstaff, Ariz.; his mother Fay Little of Madison; and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Fund of the American Heart Association, or to World Vision International, Box O, Pasadena, Calif.