Louis Hayward (Philip Grayson)
Dennis O'Keefe (Daniel O'Hara)
Louise Allbritton (Dr. Toni Neva)
Carl Esmond (Dr. Ritter von Stolb)
Raymond Burr (Krebs)
Ray Teal (Police Sergeant)
Crane Whitley (Curly)
William Tannen
Howard Negley (Feodore)
Onslow Stevens (Igor Braun)
Arthur Space (Mr. North)
John Hamilton (G.W. Hunter)
Lee Phelps
Frank Ferguson (Carl Bemish)
Jimmy Lloyd (Alison)
Bert Davidson (Potter)
Paul Bryar (Ivan)
Grandon Rhodes (Adolph Mizner)
Keith Richards (Miller)
Tamara Shayne (Landlady)
Reed Hadley (Narrator)
Art Baker (Dr. Frederick Townsend)
Lowell Gilmore (Dr. William Forrest)
Philip Van Zandt (Anton Radchek)
Charles Evans (Dr. Homer Allen)