Cary Grant (Prof. Barnaby Fulton)
Ginger Rogers (Edwina Fulton)
Charles Coburn (Oliver Oxly)
Marilyn Monroe (Lois Laurel)
Hugh Marlowe (Hank Entwhistle)
Harry Seymour (Clothing Store Salesman)
Melinda Plowman (Bit Girl)
Roger Moore (Bit Man)
Forbes Murray (Bit Man)
Brad Mora (Actor/Actress)
Ruth Warren (Laundress)
Mack Williams (Dignitary)
Isabel Withers (Laundress)
Howard Hawks (Off-screen voice in opening)
Jerry Paris (Scientist)
Louis Lettieri (Bit Boy)
Russ Clark (Policeman)
John R. McKee (Photographer)
Ray Montgomery (Policeman)
Harry Bartell (Scientist)
Charles "Heinie" Conklin (Painter)
Harry Carter (Bit Scientist)
Rudy Lee (Bit Boy)
Olive Carey (Laundress)
Mickey Little (Bit Boy)
Harry Carey, Jr. (Reporter)
Paul Maxey (Dignitary)
Robert Nichols (Garage Man)
Dabbs Greer (Cab Driver)
Esther Dale (Mrs. Rhinelander)
George Winslow (Deep-voiced Boy)
Emmett Lynn (Jimmy)
Jerry Sheldon (Detective)
Joseph Mell (Barber)
George Eldredge (Auto Salesman)
Kathleen Freeman (Mrs. Brannigan)
Mary Field (Clerk)
Olan Soule (Hotel Clerk)
Gil Stratton (Yale Man)
Harry Carey, Jr. (Detective)
Faire Binney (Dowager)
Bill McLean (Bellboy)
Robert Cornthwaite (Dr. Zoldeck)
Henri Letondal (Dr. Siegfried Kitzel)
Larry Keating (O.J. Gulverly)
Douglas Spencer (Dr. Brunner)