Cary Grant as Barnaby Fulton

Ginger Rogers as Edwina Fulton

Charles Coburn as Oliver Oxley

Marilyn Monroe as Lois Laurel

Hugh Marlowe as Hank Entwhistle

Henri Letondal as Jerome Kitzel

Robert Cornthwaite as Dr. Zoldeck

Larry Keating as G.J. Culverly

Douglas Spencer as Dr. Brunner

Esther Dale as Mrs. Rhinelander

George Winslow as Little Indian

Marjorie Holliday as Oxley Receptionist (uncredited)

Harry Carey, Jr. as Reporter (uncredited)

Nico Minardos as Man at Pool (uncredited)

Charlotte Austin as Student (uncredited)

Harry Bartell as Scientist (uncredited)

Faire Binney as Dowager (uncredited)

Tex Brodus as Club Patron (uncredited)

Olive Carey as Johnny's Mother (uncredited)

Harry Carter as Scientist (uncredited)

Melinda Casey as Girl (uncredited)

Ronnie Clark as Boy (uncredited)

Russ Clark as Policeman (uncredited)

Heinie Conklin as House Painter (uncredited)

George Eldredge as Mr. Peabody (uncredited)

Kathleen Freeman as Mrs. Brannigan - Neighbor (uncredited)

Terry Goodman as Boy (uncredited)

Dabbs Greer as Cabbie (uncredited)

Howard Hawks as Man in Opening (voice) (uncredited)

George Hoagland as Club Patron (uncredited)

Perk Lazelle as Club Patron (uncredited)

Rudy Lee as Boy (uncredited)

Louis Lettieri as Boy (uncredited)

Mickey Little as Boy (uncredited)

Emmett Lynn as Gus (uncredited)

Paul Maxey as Board Member (uncredited)

John McKee as Photographer (uncredited)

Bill McLean as Bellboy (uncredited)

Joseph Mell as Barber (uncredited)

Christopher Milne as Johnny (uncredited)

Jonathan Milne as Johnny (uncredited)

Ray Montgomery as Policeman (uncredited)

Roger Moore as Bit (uncredited)

Brad Morrow as Boy (uncredited)

Forbes Murray as Board Member (uncredited)

Robert Nichols as Garage Man (uncredited)

Jerry Paris as Scientist (uncredited)

Maudie Prickett as Clerk (uncredited)

Jimmy Roebuck as Boy (uncredited)

Harry Seymour as Clothing Store Salesman (uncredited)

Jerry Sheldon as Joe (uncredited)

Olan Soule as Pickwick Arms Clerk (uncredited)

Gil Stratton as Yale Man (uncredited)

Ruth Warren as Laundress (uncredited)

Mack Williams as Board Member (uncredited)

Isabel Withers as Laundress (uncredited)