Dorothy McGuire
Helen

George Brent
Professor Warren

Ethel Barrymore
Mrs. Warren

Kent Smith
Dr. Parry

Rhonda Fleming
Blanche

Gordon Oliver
Steve Warren

Elsa Lanchester
Mrs. Oates

Sara Allgood
Nurse Barker

Rhys Williams
Mr. Oates

James Bell
Constable

Erville Alderson
Dr. Harvey (uncredited)

Ellen Corby
Neighbour (uncredited)

Myrna Dell
Murder Victim (uncredited)

George Holmes
The Killer's 'Shadow' (uncredited)

Stanley Price
Starry-eyed Man (uncredited)

Richard Tyler
Freddy (uncredited)

Charles Wagenheim
Desk Clerk (uncredited)

Larry Wheat
Minister (uncredited)