Boris Karloff as James Lee Wong

Grant Withers as Police Capt. Sam Street

Maxine Jennings as Myra Ross

Evelyn Brent as Olga Petroff / Countess Dubois / Sophie Dome

George Lloyd as Devlin

Lucien Prival as Anton Mohl

John St. Polis as Carl Roemer

William Gould as Theodore Meisle

Hooper Atchley as Christian Wilk

John Hamilton as Simon Dayton

Wilbur Mack as Russell

Lee Tung Foo as Tchin

Lynton Brent as Tommy

Grace Wood as Mrs. Roemer

Frank Bruno as Lescardi (uncredited)

Ed Cassidy as Ambulance Doctor (uncredited)

Wheaton Chambers as Chemistry Lab Director (uncredited)

Clancy Cooper as Warehouse Man (uncredited)

George DeNormand as John (uncredited)

Lester Dorr as Coroner (uncredited)

Herbert Evans as Wilk's Butler (uncredited)

Dick Reinhart as Dock Worker (uncredited)