| Person | Type | Job | Role(s) |
|---|---|---|---|
 Arthur Conan Doyle | Crew | Writing | Story |
 Bernard B. Brown | Crew | Sound | Sound Director |
Bertram Millhauser | Crew | Writing | Screenplay |
Charles Van Enger | Crew | Camera | Director of Photography |
Edward R. Robinson | Crew | Art | Set Decoration |
Hans J. Salter | Crew | Sound | Music Director |
John B. Goodman | Crew | Art | Art Direction |
Martin Obzina | Crew | Art | Art Direction |
 Roy William Neill | Crew | Directing | Director, Producer |
Russell A. Gausman | Crew | Art | Set Decoration |
Vera West | Crew | Costume & Make-Up | Costume Design |
William Austin | Crew | Editing | Editor |
 Alec Craig | Cast | Actor | Radlik |
 Angelo Rossitto | Cast | Actor | Obongo - Pygmy (uncredited) |
 Arthur Hohl | Cast | Actor | Adam Gilflower |
Arthur Stenning | Cast | Plainclothesman (uncredited) | |
 Basil Rathbone | Cast | Actor | Sherlock Holmes |
 Belle Mitchell | Cast | Actress | Fortune Teller (uncredited) |
Brandon Beach | Cast | Actor | Carnival Patron (uncredited) |
 Dennis Hoey | Cast | Actor | Insp. Lestrade |
 Donald Stuart | Cast | Actor | Artie - Shooting Gallery Attendant (uncredited) |
 Edmund Mortimer | Cast | Actor | Casino Patron (uncredited) |
 Ethelreda Leopold | Cast | Casino Patron (uncredited) | |
 Florence Wix | Cast | Actress | Casino Patron (uncredited) |
Frank Benson | Cast | Toy Doll Attendant (uncredited) | |
 Gale Sondergaard | Cast | Actress | Adrea Spedding |
 Gene Roth | Cast | Actor | Henchman Taylor (uncredited) |
 Harry Cording | Cast | Actor | Fred Garvin (uncredited) |
Jack Deery | Cast | Actor | Casino Patron (uncredited) |
James Carlisle | Cast | Actor | Casino Patron (uncredited) |
 Jimmy Aubrey | Cast | Actor | News Vendor (uncredited) |
John Burton | Cast | Actor | Radio Announcer (uncredited) |
 John Roche | Cast | Actor | Casino Croupier (uncredited) |
 Lydia Bilbrook | Cast | Actress | Susan (uncredited) |
Marie De Becker | Cast | Charwoman (uncredited) | |
 Mary Gordon | Cast | Actress | Mrs. Hudson |
 Nigel Bruce | Cast | Actor | Dr. John H. Watson |
 Stanley Logan | Cast | Actor | Robert (uncredited) |
 Sylvia Andrew | Cast | Charwoman (uncredited) | |
 Teddy Infuhr | Cast | Actor | Larry (uncredited) |
 Vernon Downing | Cast | Actor | Norman Locke |
 Wilbur Mack | Cast | Actor | Casino Patron (uncredited) |
 William H. O'Brien | Cast | Actor | Doorman (uncredited) |
George Kirby | Cast | Actor | News Vendor (uncredited) |
| Person | Type | Job | Role(s) |
