William Powell as Dr. Lawrence 'Brad' Bradford

Jean Arthur as Paula Bradford

James Gleason as Inspector Corrigan

Eric Blore as Stokes, Bradford's Butler

Robert Armstrong as Nick Martel, Bookie

Lila Lee as Miss Prentiss, Bradford's Receptionist

Grant Mitchell as John Summers, Luxury's Owner

Erin O'Brien-Moore as Mrs. Summers

Ralph Morgan as Leroy Hutchins, War Cloud's Owner

Lucile Gleason as Mrs. Hutchins

Johnny Arthur as Mr. Frankenstein (uncredited)

Stanley Blystone as Police Radio Operator (uncredited)

Tom Brower as Police Sergeant (uncredited)

Spencer Charters as Dr. Bunting (uncredited)

Frankie Darro as Spike Salisbury (uncredited)

John Dilson as Analyst Examining Gelatin Capsule (uncredited)

James Donlan as Taxi Driver (uncredited)

Paul Fix as Lou Pender (uncredited)

Dorothy Granger as Fill-in Receptionist (uncredited)

Sam Hayes as Race Announcer (uncredited)

Rollo Lloyd as Landlord (uncredited)

Edward McWade as Minister in Film (uncredited)

Frank Reicher as Henry Strand (uncredited)

Charles Richman as Mr. Curtis (uncredited)

Syd Saylor as Detective (uncredited)

John Sheehan as Bert Murphy (uncredited)

Buster Slaven as Newsboy (uncredited)

Al St. John as Morgue Attendant (uncredited)

Henry Stone as Ray Torro (uncredited)

Bob Tansill as Joe Jerino (uncredited)

Frank M. Thomas as Mike North (uncredited)