Roger Corman Director, Producer Peter Graves Dr. Paul Nelson Actor Beverly Garland Claire Anderson Actor Lee Van Cleef Dr. Tom Anderson Actor Sally Fraser Joan Nelson Actor Charles B. Griffith Dr. Pete Shelton Actor Russ Bender Brig. Gen. James Pattick Actor Jonathan Haze Pvt. Manuel Ortiz Actor Dick Miller Sgt. Neil Actor Karen Kadler Ellen Peters Actor Paul Blaisdell The Monster (uncredited) Actor Lou Rusoff Writer James H. Nicholson Executive Producer Ronald Stein Original Music Frederick E. West Cinematographer Charles Gross Film Editing