Thomas M. McMurray, 40, assistant executive director of the Association of American Physicians and Surgeons, died Thursday at Johns Hopkins Hospital in Baltimore after surgery for a heart ailment.

Mr. McMurray worked in the administration of former Gov. Ronald Reagan of California from 1968 to 1974. During those years he served at different times as assistant cabinet secretary, special assistant to the governor and deputy secretary of California's Health and Welfare Agency.

After coming to the Washington area in January 1975, he spent three years as legislative director for Republican Whip Robert Michael in the House Representatives. In 1977 he also served on Virginia's Health Cost Containment Commission as an appointee of Gov. John N. Dalton. He was active in the successful Republican nominating campaign of the late Richard Obenshain in 1978.

Earlier this year, Mr. McMurray had been a founder of the Organizations Service Corp., which operates computer services for trade organizations. He was the corporation's president at the time of his death.

Mr. McMurray was a resident of Annandale, where he was a member of St. Micael's Catholic Church. He was active in the church's Christian Family Movement and also was active in the national "pro-life" movement.

He was a native of Peoria, Ill., and a graduate of Notre Dame University. He first came to Washington in 1965 and spent two years on the staff of the House Appropriations Committee. He was a vice president and associate publisher of a newspaper in Lewistown, Ill., before moving to California.

Survivors include his wife, Joanne, and six children, Maria, Thomas, Beth, Angie, Theresa, and Amanda, all of Annandale; his parents, Mr. and Mrs. Mitchell McMurray of Peoria, Ill.; a brother Joe, of New York City; and three sisters, Lynn Bredemyer of Chicago, Judy Schlicksup of Davenport, Iowa, and Sister Phyllis McMurray of the Order of Saint Benedict in Nauvoo, Ill.

The family suggests that expressions of sympathy be in the form of contributions to an educational trust fund set up for Mr. McMurray's children.