William Loomis, 90, a Washington barber for over 50 years until his retirement in 1966, died of renal failure Saturday at his home in Silver Spring.

A native of Gythion, Greece, Mr. Loomis came to Washington in 1905 with an uncle. He worked as a barber here and, for a short time, in Birmingham. ala., where his oath as a citizen was administered by Hugo Black, who later became a Supreme Court Associate Justice.

Mr. Loomis returned here in 1914 and, in 1919, he and a partner, Anthony Panagos, opened the National Barber Shop at 917 D Street NW. Following the death of Mr. Panagos in 1947, the shop was called the Bill Loomis Barber Shop. Mr. Loomis sold the business in 1966 to make way for the construction of the new FBI headquarters here.

He served in the Army during World War I. During World War II he was appointed to serve as a parole officer here to help local Greek boys in trouble.

Mr. Loomis married the former Evangelia Sarelakay in 1924.

He attended St. Sophia Greek Orthodox Cathedral here and was a founding member of the Cathedal and of Sts. Constantine and Helen Greek Orthodox Church here.

In addition, Mr. Loomis helped found the Hellenic Post of the American Legion here in 1919. He was made a life member of the Post in 1978.

In 1924, he was one of the founders of the Washington chapter of the American Hellenic Educational Progressive Association. He also helped found the Lelex Chapter of the Laconian Society of Washington in 1943.

In addition to his wife, of the home in Silver Spring, he is survived by a daughter, Margaret, also of the home; another daughter, Rubie Mallers, and a son, Peter, both of Ft. Wayne, Ind.; two brothers, Harilaos Loumakos, of Athens, Greece, and Antonios Loumakos, of Neohorion, Gythion. Greece; three sisters, Sophia Xanthakou, also of Athens, Panagiota Kourakou, of Kalamata, Greece, and Garifalia Pastelakou, of Maviovounio, Greece, six grandchildren and one great-grandson.