Dr. Tom Anderson
Lee Van Cleef
Claire Anderson
Beverly Garland
Sheriff N.J. Shallert
Taggart Casey
George Haskell
Thomas E. Jackson
U.S. Secretary Platt
Marshall Bradford
Gen. Carpenter
David McMahon
The Monster (uncredited)
Paul Blaisdell
Dr. Paul Nelson
Peter Graves
Joan Nelson
Sally Fraser
General James Pattick
Russ Bender
Pvt. Miguel Ortiz
Jonathan Haze
Sgt. Neil
Dick Miller
Floyd Mason
Paul Harbor
Dr. Pete Shelton
Charles B. Griffith
Ellen Peters
Karen Kadler
Director
Roger Corman
Producer
Writer
Special Effects
Creature Design
Executive Producer
Samuel Z. Arkoff
James H. Nicholson
Original Music Composer
Ronald Stein
Screenplay
Lou Rusoff
Director of Photography
Frederick E. West
Editor
Charles Gross Jr.
Makeup Artist
Larry Butterworth
Production Manager
Lou Place
Sound
Jay Ashworth
Al Overton
Philip Mitchell