David Fielding (as Skip Shimer)
Susan Turner
Asmodeus
Jim Hudson (as Frank Boers Jr.)
Vicki (as Robin Snider)
Reporter Sloan (as Jim Phillips)
Dr. Arthur Watermann (as Fritz Leiber)
Doctor Branson
Nurse
Old man in cave
The Orderly
Doctor on Tape Recorder (voice) (uncredited)
Detective Harrison (uncredited)
Reporter Sloan (voice) (uncredited)
The Green Giant