Retired Navy Capt. William B. Regan, 50, a resident of the Washington area since he was assigned to the staff of the Joint Chiefs of Staff in 1969, died of cancer Friday at the Bethesda Naval Hospital.

Capt. Regan retired from the Navy in 1973. Since then, he had worked in the mortgage business. He was employed by the Mortgage Investment Corp. of Falls Church until illness forced his retirement about a year ago.

He was born in Providence, R.I., and grew up there. He enlisted in the Coast Guard and served for four years. He later earned a bachelor's degree at the University of Rhode Island and was commissioned in the Navy in 1950. He saw service in Vietnam and later commanded the destroyer H.R. Dickson before being assigned to the staff of the Joint Chiefs in the Pentagon.

His decorations include the Legion of Merit and the Navy Commendation Medal.

Capt. Regan was a member of the Retired officers Association.

Survivors include his wife, Shirley, of the home in Fairfax; two sons, Richard and Mark, also of the home, and his mother, Mrs. John T. Regan, of Providence.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society, or to the Chantilly Fire and Rescue Squad, Chantilly.