The SDI was founded in 1998 by the merger of the Italian Socialists (Enrico Boselli, Roberto Villetti and Ottaviano Del Turco), the Italian Democratic Socialist Party (Gian Franco Schietroma and Giorgio Carta), a portion of the Labour Federation, a portion of the Socialist Party (Ugo Intini) and the Socialist League (Claudio Martelli and Bobo Craxi).
Ugo Rondinone | Ugo Foscolo | Ugo Mifsud Bonnici | Ugo Rossi | Ugo Mulas | Ugo Tognazzi | Ugo Pasquale Mifsud | Ugo Mattei | Ugo Fano | Ugo Savarese | Ugo Poletti | Ugo Monye | Ugo Intini | Ugo Falena | Ugo Ehiogu | Ugo Cavallero | Ugo Betti | Ugo Balzani | UGO | Pier Ugo Calzolari | Iginio Ugo Tarchetti |