In the autumn of 1989, the materials of the 18th Stockholm Congress of Socialist International reached Chişinău from Estonia and did stir up a lot of debates among those dissatisfied with the political realities in Moldovan SSR.

The Founding Conference elected Oazu Nantoi, Ion Negură, Alexandru Coșelev as the Party Co-Chairpersons.

[5] On the eve of 1996 presidential elections, Social Democrats were the only ones to openly support Petru Lucinschi.

Incumbent Party Chairperson, Oazu Nantoi, attended in November 1999 the 21st Paris Congress of the Socialist International.

They didn't agree with the decision of their leader, Mihai Petrache, to abandon the process of negotiation regarding the unification of social democrats that had started some months before.

In February 2010, it was reported that approximately 11,000 members of the PSD defected to the rival centre-left Democratic Party of Moldova.