John Carradine as Dr. Charles Conway

Myron Healey as Mark Houston

Allison Hayes as Grace Thomas

Marilyn Buferd as Dr. Sharon Gilchrist

Tor Johnson as Lobo

Arthur Batanides as Danny Green

Sally Todd as Natalie Andries

Harry Fleer as Harry Jedrow

Roy Gordon as Dr. Loren Wright

Guy Prescott as Police Captain George Reagan

Raymond Guth as Police Officer Miller

Paul McWilliams as Police Officer Ed

Gloria Petroff as Screaming Woman

Karl Johnson as Monster in Basement (uncredited)

Harry Wilson as Monster in Basement (uncredited)