Arthur Franz as Dr. Jim Barker

Virginia Huston as Carol Stafford

Cameron Mitchell as Steve Abbott

John Litel as Dr. Lane

Richard Gaines as Prof. Jackson

Morris Ankrum as Ikron

Marguerite Chapman as Alita

Lucille Barkley as Terris

Robert Barrat as Tillamar

Edward Earle as Justin (uncredited)

William Forrest as General (uncredited)

David Bond as Ramay (uncredited)

Stanley Blystone as Councilman (uncredited)

Tristram Coffin as Commentator (uncredited)

Everett Glass as Montar (uncredited)

Trevor Bardette as Alzar (uncredited)