It was founded on July 27, 1990 by Slobodan Milošević as a merger of Milošević's League of Communists of Serbia (Serbian section of the League of Communists of Yugoslavia), and the Socialist Alliance of the Working People of Serbia (the Serbian branch of the Socialist Alliance of the Working People of Yugoslavia), led by Radmila Anđelković.
The party won the first elections in Serbia with 194 out of 250 seats and 46.1% of the popular vote. From 1992 it governed in coalition with other parties – initially with the Serbian Radical Party, and from 1993 with the New Democracy Party. They also contested elections in coalition with Yugoslav Left, a party led by Milošević's wife Mirjana Marković.
With the ousting of Milošević in 2000, the party became a part of the opposition. In the 2003 Serbian general elections, the party won 7.6% of the popular vote and 22 out of 250 seats in the National Assembly of Serbia. In 2004, however, its candidate in the presidential election, Ivica Dačić, placed fifth with 3.6% of the vote.
In 2007 parliamentary elections, the Socialist Party of Serbia won 16 seats with 227,580 or 5.64 percent of votes. It formed a sole parliamentary group, with Ivica Dačić as president and Žarko Obradović as vice-president. It won 14 seats outright while a single seat was given to its new partner, the Movement of Veterans of Serbia and non-partisan Borka Vučić, who became the transitional speaker, also received a seat.
In Serbian parliamentary election, 2008, the Socialist Party of Serbia and the Party of United Pensioners of Serbia (PUPS) have strengthened their links by forming a coalition, on which United Serbia and Movement of Veterans of Serbia were present. Coalition won 23 seats with 313,896 or 7.58 percent of votes. SPS and its coalition partners entered post-election coalition with For a European Serbia and formed new Government of Serbia. SPS have First Deputy of the government and 4 minister while PUPS have 1 minister.