Malcolm Ernest Clark, 56, a retired chief of the energy conservation office of the D.C. Department of General Services who was active in the Columbia Baptist Church in Falls Church, died of cancer Tuesday at his home in McLean.

Mr. Clark was born in Monroe, La., and grew up in Texas. He was commissioned a second lieutenant in the Marine Corps during World War II and served in China when the war was over. He was called to active duty during the Korean War.

In the meantime, Mr. Clark earned a degree in civil engineering at Louisiana Tech University. He later was a civil engineer in Kansas and a factory manager in Texas. In 1958, he went to work for the Army Corps of Engineers. In 1961 and 1962, he was a project engineer on the construction of Titan II missile sites in Arizona. He later worked in California.

In 1967, Mr. Clark transferred to Washington and became the assistant to the chief of the eastern section of the Air Force construction division in the Corps of Engineers.

In 1970, he joined the D.C. Department of General Services, where he was chief of the management analysis division and then chief of the improvements and maintenance planning division. From 1977 until he retirement last year, he was chief of the department's energy conservation office.

Mr. Clark had been a member of the Columbia Baptist Church since moving to this area. For 10 years he was its church in training director. He also was chairman of the deacons, director of the Sunday School department, chairman of the personnel committee and a member of the finance committee.

Survivors include his wife, D'Ella Abington Clark, of McLean; two sons, Malcolm E. III, also of MacLean, and Albert D., who is serving in the Army at Fort Rucker, Ala.; his mother, Erma Quinney Clark of El Paso; a brother, George Clark, also of El Paso; a sister. Mrs. Clyde Nelson of Clint, Tex., and two grandsons.

The family suggests that expressions of sympathy be in the form of contributions to the Malcolm Clark Memorial Fund, Columbia Baptist Church, Falls Church, Va.