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)