Dr. Clem C. Williams, 93, a Washington dentist for more than 50 years before his retirement in 1974, died of cardio-respiratory arrest Tuesday at the John Knox Village Medical Center in Tampa, Fla.

A former longtime Washington resident, Dr. Williams moved to Tampa after retiring.

Born in Corso, Mo., he came to Washington in 1913 and worked for the Department of the Post Office, now the Postal Service, while attending Georgetown University's dental school. He began his private dental practice here after graduating in 1916.

In the mid-1920s, Dr. Williams was an instructor in dental ethics and jurisprudence at Georgetown University. He served on active duty with the Naval Dental Corps Reserve in 1918-19 and, during World War II, served as head of dental examining for the Selective Service Board at Providence Hospital.

He was elected a life member of the D. C. Dental Society in 1953.

Dr. Williams was a member of the D. C. Round Table, the Fossils, the Mithras Lodge of Perfection of the Scottish Rite and a former member of Chevy Chase Presbyterian Church here.

His first wife, the former May Winn, died in 1961, and his second wife, the former Margaret W. Taylor, died in January.

Survivors include two sons, Dr. CLEM C. Jr. of Greencastle, Ind., and retired Army Col. Murray W. of St. Joseph's Mo.; a sister, Carrie A. Williams of Tampa, six grandchildren and two great-grandchildren.