Kenneth Tobey as Captain Patrick Hendry

Margaret Sheridan as Nikki

Robert Cornthwaite as Dr. Arthur Carrington

Douglas Spencer as Ned 'Scotty' Scott

James Young as Lt. Eddie Dykes

Dewey Martin as Crew Chief Bob

Robert Nichols as Lt. Ken 'Mac' Erickson

William Self as Corporal Barnes

Nicholas Byron as Tex Richards

Eduard Franz as Dr. Stern

George Fenneman as Dr. Redding

Paul Frees as Prof. Voorhees

Everett Glass as Prof. Wilson

Norbert Schiller as Dr. Lorenz

Edmund Breon as Prof. Ambrose

John Dierkes as Dr. Chapman

Sally Creighton as Mrs. Chapman

James Arness as 'The Thing'

David McMahon as Gen. Fogarty

Bill Neff as Bill Stone (uncredited)