Boris Karloff
Dr. Janos Rukh
Béla Lugosi
Dr. Felix Benet
Frank Lawton
Ronald Drake
Frances Drake
Diana Rukh
Violet Kemble Cooper
Mother Rukh
Beulah Bondi
Lady Arabella Stevens
Walter Kingsford
Sir Francis Stevens
Paul Weigel
Monsieur Noyer
Frank Reicher
Professor Meiklejohn
Georges Renavent
Chief of the Surete
May Beatty
Mme. LeGrand (uncredited)
Paul McAllister
Papa LaCosta (uncredited)
Nydia Westman
Briggs (uncredited)
Ynez Seabury
Celeste (uncredited)
