Italian Democratic Socialist Party

The Italian Democratic Socialist Party (Italian: Partito Socialista Democratico Italiano, PSDI), also known as Italian Social Democratic Party, was a social-democratic political party in Italy. The longest serving partner in government for Christian Democracy, the PSDI was an important force in Italian politics, before the 1990s decline in votes and members. The party's founder and longstanding leader was Giuseppe Saragat, who served as President of the Italian Republic from 1964 to 1971. Compared to the like-minded Italian Socialist Party on the centre-left, it was more centrist, but it identified with the centre-left.

After a rightward shift in the 1990s, which led some observers to question the PSDI as a social democratic party, it was expelled from the European Socialist Party. When Enrico Ferri founded with Luigi Preti the current European Liberal Social Democracy (SOLE), which was in favour of an alliance with Silvio Berlusconi's centre-right coalition, the choice was stigmatized by the PES and the Socialist International, and an official statement was issued. In January 1995, the party congress put the current of Ferri and Preti in the minority and elected Gian Franco Schietroma as secretary. After the party was disbanded in 1998, the majority went to the Socialist Party of the centre-left coalition, while the party's right-wing current joined centre-right coalition parties. In 2004, the party was established with the same name, Italian Democratic Socialist Party, which remains a minor party associated with both centre-left and centre-right coalitions.