Victor A. Fediay, 79, a former Library of Congress researcher on Russian and East European affairs who became a consultant and lobbyist in the field of foreign affairs, died of a heart attack July 20 at Sibley Memorial Hospital.

Mr. Fediay, who was stricken at his home in Washington, was born in Mileov, Russia. In 1919, he and his family moved to Warsaw. He graduated from the University of Warsaw, where he received degrees in law and economics.

In 1948, he moved to Washington and went to work for the Library of Congress as a researcher. He remained there until 1969, when he joined the staff of Sen. Strom Thurmond (R-S.C.).

In 1975, Mr. Fediay co-founded the Institute of American Relations, an educational and research organization that organized conferences in this country and abroad and published newsletters. In 1979, he founded the Foreign Affairs Council, a lobbying organization. He was president of both groups until about 1984.

Since then, Mr. Fediay had been a lobbyist and consulant, with clients ranging from various committees of Congress and government agencies to the Christian Crusade.

Mr. Fediay was a member of St. John the Baptist Russian Orthodox Cathedral in Washington.