Spofford G. English, 65, a retired chemist and government official who had worked for many years with the Atomic Energy Commission and then the Energy Research and Development Administration, died Monday at his home in Bethesda. He had cancer.

He joined the Atomic Energy Commission shortly after it was established in 1947 and was chief of its chemistry branch in the division of research until 1960. He also was special assistant to the general manager for disarmament from 1959 to 1961, deputy director of the division of research in 1960 and 1961, and assistant general manager for research and development from 1961 to 1973.

Dr. English then became associate director of the division of physical research, remaining in that capacity after the AEC became part of the Energy Research and Development Administration in 1975. He retired in 1976.

An advocate of disarmament, he had served with the U.S. delegations to the United Nations Disarmament Conference in England in 1955 and the Conference for the Discontinuance of Nuclear Weapons Tests in Switzerland in 1959. He received the AEC's Outstanding Service Award in 1956.

Dr. English was born in Mount Pleasant, Tenn. He was a graduate of the University of Oklahoma, where he was elected to Phi Beta Kappa and where he also earned a master's degree. He got his doctorate from the University of California at Berkeley.

In 1942 and 1943, Dr. English was a group leader with the Manhattan Project, which developed the atomic bomb, at the University of Chicago. He then served for three years as a section chief in the chemistry division of the Clinton Laboratories at Oak Ridge, Tenn. He taught chemistry at the University of California at Berkeley before joining the AEC.

He is survived by his wife, Muriel F., of Bethesda, and three daughters, Susan P., of Alexandria, Elizabeth H., of Brooklyn, and Helen W., of London, England.