E. Wallace Thomas, 55, president and founder of Crew Associates, a Rockville computer consulting firm, died Monday at the A. Barton Memorial Hospital in Ogdensburg, N.Y., after a heart attack. Mr. Thomas, a resident of Rockville, was stricken while vacationing near Colton, N.Y.

Mr. Thomas was born in Washington and graduated from Mount Rainier High School. During World War II, he served with the Army Air Forces in India and Burma as a radar operator.

After the war, he returned here and started his career in the computer field at what is now the David Taylor Naval Ship and Research Center. He later worked in the private sector for Burroughs Corporation and Honeywell, Inc.

About 1968, he founded Crew Associates and was its president at the time of his death.

His marriage to Frances Thomas ended in divorce.

Survivors include his two daughters, Barbara Killon of Reston and Cheryl Lea Thomas of Port Tobacco, Md.; a son, Earl Thomas of Silver Spring; a sister, Elaine Bothe of Washington, and two brothers, Lloyd of Chesapeake Beach, Md., and Allan of Annapolis.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Fund of the American Heart Association.