Lloyd A. Brewer, 59, executive vice president for administration of the Equitable Life Insurance Co., died of cancer Monday at his home in Bethesda.

He joined Equitable at the age of 17 as an office clerk, and became an agent several years later. He also earned a law degree from Southeastern University, where he attended evening classes.

During World War II, Mr. Brewer served as an Army officer and was assigned to an Office of Strategic Services unit in China.

Returning to Equitable after the war, he joined its marketing department. He became senior vice president and secretary of the company in 1968. He became executive vice president in 1975.

Mr. Brewer served on the boards of both Equitable Life and its parent holding company, the Equitable General Corporation. He had attended a number of schools in his field and was a chartered life underwriter. He was active in numerous life insurance industry associations.

A native of Rockville, he was a life-long member of Christ Episcopal Church of Rockville. He belonged to the Congressional Country Coub.

He is survived by his wife, Ellen, of the home; a brother, Charles A., of Rockville; four stepchildren, Mrs. Ralph Nelson, of Potomac, William R. Pumphrey III, of Winchester, Ky., Robert A. Pumphrey Jr., of Hood, Va., and Richard G. Pumphrey, of Rome, Ga., and eight stepgrandchildren.