Preston Foster as Dr. Erik von Steiner

Philip Carey as Dr. Steve Connors

Merry Anders as Carol White

John Hoyt as Dr. Varno

Dennis Patrick as Councilman Willard

Joan Woodbury as Gadra

Steve Franken as Danny McKee, the Electrician

Berry Kroeger as Preston

J. Edward McKinley as Raymond

Delores Wells as Reena

Gloria Leslie as Councilwoman

Molly Glessing as Android

Peter Strudwick as The Mutant

Margaret Seldeen as Miss Hollister

Forrest J. Ackerman as Square-Frame Technician