Farley Granger as Guy Haines

Ruth Roman as Anne Morton

Robert Walker as Bruno Antony

Leo G. Carroll as Sen. Morton

Patricia Hitchcock as Barbara Morton

Kasey Rogers as Miriam Haines

Marion Lorne as Mrs. Antony

Jonathan Hale as Mr. Antony

Howard St. John as Police Capt. Turley

John Brown as Prof. Collins

Norma Varden as Mrs. Cunningham

Robert Gist as Det. Leslie Hennessey

Brooks Benedict as Tennis Umpire (uncredited)

John Doucette as Det. Hammond (uncredited)

Harry Hines as Man Under Merry-Go-Round (uncredited)

Alfred Hitchcock as Man Boarding Train Carrying a Double Bass (uncredited)

Paul McGuire as Train Passenger (uncredited)

Oliver Cross as Party Guest (uncredited)

Tom Ferrandini as Linesman (uncredited)

Stuart Hall as Tennis Match Spectator (uncredited)