Basil Rathbone as Sherlock Holmes

Nigel Bruce as Doctor Watson

Lionel Atwill as Professor Moriarty

William Post Jr. as Dr. Franz Tobel

Kaaren Verne as Charlotte Eberli

Dennis Hoey as Inspector Lestrade

Holmes Herbert as Sir Reginald

Mary Gordon as Mrs. Hudson

Harry Cording as Jack Brady (uncredited)

Harold De Becker as Peg Leg (uncredited)

Paul Fix as Mueller (uncredited)

Henry Victor as Professor Frederic Hoffner (uncredited)

John Burton as RAF Officer (uncredited)

Paul Bryar as Swiss Waiter (uncredited)

Whit Bissell as London Bobbie (uncredited)

Rudolph Anders as Braun (uncredited)

Colin Kenny as Scotland Yard Detective (uncredited)

George Burr Macannan as Gottfried (uncredited)

Harry Woods as Kurt (uncredited)