Timmie Merrinoe
Richard Eyer
Dr. Tom Merrinoe
Philip Abbott
Prof. Foster
Jefferson Dudley Searles
Martin / Computer
Alfred Linder
1st Gate Sergeant
Ralph Votrian
2nd Gate Sergeant
Michael Miller
Capt. McLaren (uncredited)
Rayford Barnes
Miss Vandergrift (uncredited)
Helen Kleeb
Scientist (uncredited)
Alvy Moore
Young soldier (uncredited)
Gary Vinson
Robby the Robot (voice) (uncredited)
Marvin Miller
Mary Merrinoe
Diane Brewster
Gen. Swayne
Harold J. Stone
Prof. Frank Allerton
Robert H. Harris
Col. Macklin
Dennis McCarthy
Arthur Kelvaney
Alexander Lockwood
Prof. Baine
John O'Malley
Dr. Bannerman
Gage Clarke
Prof. Zeller
Than Wyenn
Original Music Composer
Les Baxter
Director
Herman Hoffman
Screenplay
Cyril Hume
Story
Edmund Cooper
Producer
Nicholas Nayfack
Editor
John Faure
Art Direction
Merrill Pye
Set Decoration
Darrell Silvera
Special Effects
Irving Block
Louis DeWitt
Jack Rabin
Director of Photography
Harold E. Wellman
Production Manager
Gus Schroeder