Kenneth Tobey

Captain Patrick Hendry

Margaret Sheridan

Nikki

Robert Cornthwaite

Dr. Arthur Carrington

Douglas Spencer

Ned 'Scotty' Scott

James Young

Lt. Eddie Dykes

Dewey Martin

Crew Chief Bob

Robert Nichols

Lt. Ken 'Mac' Erickson

William Self

Corporal Barnes

Nicholas Byron

Tex Richards

Eduard Franz

Dr. Stern

George Fenneman

Dr. Redding

Paul Frees

Prof. Voorhees

Everett Glass

Prof. Wilson

Norbert Schiller

Dr. Lorenz

Edmund Breon

Prof. Ambrose

John Dierkes

Dr. Chapman

Sally Creighton

Mrs. Chapman

James Arness

'The Thing'

David McMahon

Gen. Fogarty

Bill Neff

Bill Stone (uncredited)

Robert Stevenson

Capt. Smith - Fogarty's Aide (uncredited)