Paolo Villaggio as Dr. Jekyll / Mr Hyde

Edwige Fenech as Barbara Wimply

Gianrico Tedeschi as James / Jeeves

Gordon Mitchell as Pretorius

Paolo Paoloni as Professor

Guerrino Crivello as Student

Eolo Capritti as Henchman

Francesco Anniballi as Henchman

Walter Williams as PANTAC Top President

Clemente Ukmar as Henchman

Geoffrey Copleston as Archibald Gold

Paola Arduini as Stewardess

Angelo Boscariol as PANTAC Board Member (uncredited)

Luciano Foti as Class Member (uncredited)

Alfonso Giganti as Industrialist (uncredited)

Juba Kennerley as Gentleman (uncredited)

Giuseppe Marrocco as PANTAC Board Member (uncredited)

Fulvio Mingozzi as PANTAC Board Member (uncredited)

Alessandro Tedeschi as Professor introducing Jekyll (uncredited)

Luciano Zanussi as PANTAC Board Member (uncredited)