Ingrid Bergman as Dr. Constance Petersen

Gregory Peck as John Ballantine

Leo G. Carroll as Dr. Murchison

Michael Chekhov as Dr. Alexander Brulov

John Emery as Dr. Fleurot

Steven Geray as Dr. Graff

Paul Harvey as Dr. Hanish

Erskine Sanford as Dr. Galt (uncredited)

Norman Lloyd as Mr. Garmes

Donald Curtis as Harry

Rhonda Fleming as Mary Carmichael

Bill Goodwin as House detective

Art Baker as Det. Lt. Cooley

Regis Toomey as Det. Sgt. Gillespie

Wallace Ford as Hotel masher

Jean Acker as Matron (uncredited)

Irving Bacon as Railway Gateman (uncredited)

Richard Bartell as Ticket Taker (uncredited)

Harry Brown as Gateman (uncredited)

Joel Davis as John Ballantine as a Boy (uncredited)

Jacqueline deWit as Nurse (uncredited)

Edward Fielding as Dr. Anthony Edwardes (uncredited)

Alfred Hitchcock as Man Leaving Elevator (uncredited)

Teddy Infuhr as John Ballantine's Brother (uncredited)

Victor Kilian as Sheriff (uncredited)

George Meader as Hallett - Railroad Clerk (uncredited)

Matt Moore as Policeman at Train Station (uncredited)

Constance Purdy as Dr. Brulov's Housekeeper (uncredited)

Addison Richards as Police Captain (uncredited)

Janet Scott as Norma Cramer (uncredited)

Clarence Straight as Secretary at Police Station (uncredited)

Dave Willock as Bellboy (uncredited)