Edward Thomas Brennan, 58, a Foreign Service officer and a former counselor for refugee and migration affairs for the U.S. Mission to the United Nations in Switzerland, died Tuesday at the National Institute of Health clinical center. He had leukemia.

Mr. Brennan joined the Foreign Service in 1941. He was in charge of diplomatic courier operations for Latin America, the South Pacific and Northern Europe, and later was assigned to France, Germany, the Phillippines, Tunisia and the Central African Republic, where he was deputy chief of mission.

Before being named counselor for refugee and migration affairs in 1975, he served as a consul general in Salonika, Greece, for about five years. He had been on sick leave since January.

During his career, he also was an adviser on international affairs to the Department of the Navy, a delegate to the 1970 UNESCO conference in Paris, and an official of the U.N. High Commission for Refugees.

Mr. Brennan was born in Toorak, Australia, and came to this area with his family at an early age. He earned a bachelor's degree in foreign service from Georgetown University.

He served as a Navy aviator from 1942 to 1947 and as a Navy Reserve aviator during the Korean conflict.

He received two Superior Service awards from the State Department and an Exceptional Civilian Service commendation from the Air Force.

He was a member of the American Foreign Service Association, the Naval Institute and the Army & Navy Club in Washington.

Survivors include his wife, Denise M., and two sons, Edward T. Jr. and Peter M., and a daughter, Nizette, all of the home in Bethesda; another son, Kevin C., with the U.S. Embassy in Prague, and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society's leukemia research fund.