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)