 Peter LorreMr. Moto | Mr. Moto |
 Joseph SchildkrautHendrik Manderson | Hendrik Manderson |
 Lionel AtwillProf. Roger Chauncey Hildebrand | Prof. Roger Chauncey Hildebrand |
 Virginia FieldEleanor Kirke | Eleanor Kirke |
 John 'Dusty' KingHoward Stevens | Howard Stevens |
| IIva StewartSusan French | Susan French |
 G.P. HuntleyArchie Featherstone | Archie Featherstone |
 Victor VarconiPaul Borodoff | Paul Borodoff |
 John BleiferWendling | Wendling |
 Honorable WuWong | Wong |
 Morgan WallaceDavid Perez | David Perez |
 Anthony WardeJoe Rubla | Joe Rubla |
 Harry StrangMuseum Guard O'Hara | Museum Guard O'Hara |
 John DavidsonPrince Suleid | Prince Suleid |
| EEddie AbdoArabian Officer (uncredited) | Arabian Officer (uncredited) |
 Carol AdamsMinor Role (uncredited) | Minor Role (uncredited) |
 Jimmy AubreyBum (uncredited) | Bum (uncredited) |
 Brooks BenedictGangster (uncredited) | Gangster (uncredited) |
 Willie BestDriver (uncredited) | Driver (uncredited) |
 Stanley BlystoneShip's Captain (uncredited) | Ship's Captain (uncredited) |
 George ChandlerCameraman (uncredited) | Cameraman (uncredited) |
 Jack Rube CliffordSergeant on Motorcycle (uncredited) | Sergeant on Motorcycle (uncredited) |
| CChick CollinsDriver of Armored Car (uncredited) | Driver of Armored Car (uncredited) |
| JJames ConatyShip Passenger (uncredited) | Ship Passenger (uncredited) |
 Gino CorradoMuseum Exhibit Attendee (uncredited) | Museum Exhibit Attendee (uncredited) |
 Lester DorrReporter (uncredited) | Reporter (uncredited) |
 Ralph DunnPolice Guard (uncredited) | Police Guard (uncredited) |
 Jack GarganMuseum Exhibit Attendee (uncredited) | Museum Exhibit Attendee (uncredited) |
 William GouldPolice Captain (uncredited) | Police Captain (uncredited) |
| BBobby HaleSteward (uncredited) | Steward (uncredited) |
