Walter Pidgeon
Dr. Edward Morbius
Anne Francis
Altaira Morbius
Leslie Nielsen
Commander John J. Adams
Warren Stevens
Lt. 'Doc' Ostrow
Jack Kelly
Lt. Jerry Farman
Earl Holliman
Cookie
Richard Anderson
Chief Engineer Quinn
George D. Wallace
Bosun
Robert Dix
Crewman Grey
Jimmy Thompson
Crewman Youngerford
James Drury
Crewman Strong
Harry Harvey Jr.
Crewman Randall
Roger McGee
Crewman Lindstrom
Peter Miller
Crewman Moran
Morgan Jones
Crewman Nichols
Richard Grant
Crewman Silvers
James Best
Crewman (uncredited)
William Boyett
Crewman (uncredited)
Les Tremayne
Narrator (uncredited) (voice)
Frankie Darro
Robby the Robot (interior) (uncredited)
Marvin Miller
Robby the Robot (voice) (uncredited)