Edward Connell

David Fielding

Barbara Hewitt

Susan Turner

Jack Woods

Asmodeus

Frank Bonner

Jim Hudson

Robin Christopher

Vicki

James Phillips

Reporter Sloan

Fritz Leiber Jr.

Dr. Arthur Watermann

Patrick Burke

Doctor Branson

Sharon Gray

Nurse

Louis Clayton

Old man in cave

Norvelle Brooks

Irving L. Lichtenstein

James Dwion

The Orderly

Forrest J. Ackerman

Doctor on Tape Recorder (voice) (uncredited)

Jack H. Harris

Detective Harrison (uncredited)

Chuck Niles

Reporter Sloan (voice) (uncredited)

Jim Duron

The Green Giant