Paulette Goddard
— Lucretia Borgia
John Lund
— Alfonso D'Este
Macdonald Carey
— Cesare Borgia
Albert Dekker
— Vanetti
John Sutton
— Prince Bisceglie
Raymond Burr
— Michelotto
Donald Randolph
— Tiziano
Charles Dayton
— Bastino
Anthony Caruso
— Captain of the Guard
Dick Foote
— Negligent Sentry
William Farnum
— Conti Peruzzi
Kate Drain Lawson
— Gemma
Nicholas Joy
— Chamberlain
Fritz Leiber
— Filippo
Rose Hobart
— Lady Eleanora
Douglas Spencer
— False Physician
Nestor Paiva
— Mayor
Frank Puglia
— Bolfi
Houseley Stevenson
— Councillor
Robert Greig
— Councillor
Don Beddoe
— Councillor
Ian Wolfe
— Councillor (uncredited)