Dr. Durward V. Sandifer, 80, a retired Foreign Service and State Department official and a professor emeritus at American University's School of International Service, died of cancer Sunday at Georgetown University Hospital. He was a resident of Washington and Silver Spring.

During a career with the State Department that spanned more than 25 years, Dr. Sandifer served as a legal adviser in Washington and held several posts overseas. His special field was United Nations affairs.

Dr. Sandifer moved to Washington and joined the State Department as an assistant legal adviser in 1934. During World II, he was assistant division chief for international organizations, and from 1945 to 1947 he was division chief.

He attended the Dumbarton Oaks Conference, the meeting laying the groundwork for the United Nations organizations, and was chief technical officer of he U.S. delegation to the United Nations conference in San Francisco in 1945.

Following the war, he was a delegate to UNESCO, the World Health Organization and executive officer and adviser to the U.S. delegation to the U.N. General Assembly. From 1949 to 1953, he was deputy assistant secretary of state for United Nations affairs.

Dr. Sandifer was the political affairs counselor at the U.S. Embassy in Buenos Aires from 1954 to 1957 and was a State Department and foreign affairs adviser at the Industrial College of the Armed Forces at the time he retired from the Foreign Service in 1960.

For the next 10 years, Dr. Sandifer taught at American University's School of International Service before retiring as professor emeritus in 1970. During this period, he also was an officer of the Inter-American Commission on Human Rights.

Dr. Sandifer was a member of the American Society of International Law and the American and Federal bar associations. He was the author of a number of works on international relations and international law.

A native of Tamalco, Ill., and a 1924 graduate of Eureka College in Eureka, Ill., Dr. Sandifer earned master's and doctoral degrees at Columbia University. In 1931, he also earned a law degree at Columbia.

He taught rhetoric and argumentation and was debate team coach at Eureka College from 1924 to 1927. He taught international law at Rutgers University in New Jersey before moving to Washington in 1934.

His first wife, the former Irene Reiterman, whom he married in 1925, died in 1977.

Dr. Sandifer's survivors include his wife, the former Virginia Tannar of Washington; a daughter, Muriel Munroe of Anchorage, Alaska; two sisters, Courtney Ray of Belleville, Ill., and Marcella Wiley of De Kalb, Ill., and four grandchildren.