Paul Francis Gaughran, 63, director of security at the old Atomic Energy Commission until he retired in 1973, died of cancer Tuesday at his home in Bethesda.

Mr. Gaughran was born in Boston and graduated from Boston College in 1936. He worked for the city of Boston until 1941, when he was drafted into the Army. After service in China and India, he was transferred to Washington in 1946 as a major on the Army general staff.

After leaving the service, he joined the Atomic Energy Commission, whose functions now are carried out by the Department of Energy, as a security officer. He took graduate courses in administration at American University.

After his retirement he was a consultant to the congressional Joint Committee on Atomic Energy from 1975 to 1977.

Mr. Gaughran was a member of the parish of St. Jane Frances de Chantal Catholic Church in Bethesda and of the John Carroll Society. He also belonged to the Bethesda Country Club.

Survivors include his wife, Charlotte, and a daughter, Ellen, both of the home, and a brother, Edward, of South Weymouth, Mass. A son, Robert, died in 1973.

The family suggests that expressions of sympathy be in the form of contributions to the Vincent T. Lombardi Cancer Research Center, Georgetown University Hospital, Washington, 20007.