Louis Hayward
饰 Philip 'Scotty' Grayson
Dennis O'Keefe
饰 Daniel F. O'Hara
Louise Allbritton
饰 Dr. Anastasia 'Toni' Neva
Carl Esmond
饰 Dr. Ritter von Stolb
Onslow Stevens
饰 Igor Braun
Art Baker
饰 Dr. Frederick Townsend
Lowell Gilmore
饰 Dr. William Forrest
Philip Van Zandt
饰 Anton Radchek
Charles Evans
饰 Dr. Homer Allen
Frank Ferguson
饰 Carl Bemish
Reed Hadley
饰 Narrator (voice)
Ray Teal
饰 Police Sergeant
William Tannen
饰 FBI Chemist
Gale Storm
饰 Voice on Tape Recorder
Tamara Shayne
饰 Mrs. Ecko, the Landlady
Keith Richards
饰 FBI Agent Miller
Grandon Rhodes
饰 Adolph Mizner
Steve Pendleton
饰 Police Detective Gaines
