Richard Basehart as Alan Spender

Valentina Cortese as Victoria Kowelska

William Lundigan as Major Marc Bennett

Fay Baker as Margaret

Gordon Gebert as Christopher

Steven Geray as Dr. Burkhardt

Herbert Butterfield as Joseph C. Callahan

Kei Thin Chung as Kei - Houseboy

John Burton as Mr. Whitmore

Katherine Meskill as Mrs. Whitmore

Mario Siletti as Tony, the Grocer

Charles Wagenheim as Man At Accident

David Clarke as Mechanic

Tamara Schee as Maria

Natasha Lytess as Karin Dernakova

Ashmead Scott as Inspector Hardy

Tom McDonough as Farrell

Mari Young as Chinese Singer

Steve Carruthers as Restaurant Guest (uncredited)

Harry Carter as Detective Ellis (uncredited)

Spencer Chan as Chinese Cook (uncredited)

Sonia Charsky as Bit Role (uncredited)

Geraldine Jordan as Minor Role (uncredited)

Don Kohler as Chemist (uncredited)

Roger McGee as G.I. (uncredited)

Leslie K. O'Pace as U.N.R.A Sergeant (uncredited)

Henry Rowland as Sergeant, Interpreter (uncredited)

Jeffrey Sayre as Police Stenographer (uncredited)

Glen Walters as Bit Role (uncredited)