Barbara Steele as Helen Karnstein / Mary Karnstein

George Ardisson as Baron Kurt Hummel

Halina Zalewska as Elizabeth Hummel / Adele Karnstein

Umberto Raho as Von Klage

Laura Nucci as Grumalda

Giuliano Raffaelli as Count Humboldt

Nello Pazzafini as Monk

Jeffrey Darcey as The Messenger

Aldo Barozzi as Plague Victim (uncredited)

Mario Casella as Gorca (uncredited)

Severino D'Ottavi as Party Guest (uncredited)

Alba Maiolini as Wife of Plague Victim (uncredited)

Aldo Massasso as The Priest (uncredited)

Enzo Mondino as Villager at the Execution (uncredited)

Piero Pastore as Baron Von Letz (uncredited)

Sylvia Sorrente as Gorca's Wife (uncredited)

Terry Velasco as Gorca's Daughter (uncredited)