John Carradine as Cosmic Man

Bruce Bennett as Dr. Karl Sorenson

Angela Greene as Kathy Grant

Paul Langton as Col. Matthews

Scotty Morrow as Ken Grant

Lyn Osborn as Sgt. Gray

Walter Maslow as Dr. "Rich" Richie

Herbert Lytton as Gen. Knowland

Ken Clayton as Master Sergeant

Harry Fleer as Bill, the Park Ranger

John Erman as Radar Operator

Dwight Brooks as Major

Hal Torey as Dr. Steinholtz

Alan Wells as Sergeant