The Democratic Left Alliance (Polish: Sojusz Lewicy Demokratycznej) was a social-democratic[7][8][9] political party in Poland.

[10] The main support for SLD came from middle-rank state sector employees, retired people, former communist Polish United Workers Party (PZPR) and All-Poland Alliance of Trade Unions (OPZZ)[11] members and those who were unlikely to be frequent church-goers.

[12] The core of the coalition (Social Democracy of the Republic of Poland) rejected concepts such as lustration and de-communization, supported a parliamentarian regime with only the role of an arbiter for the president and criticized the right-wing camp for the introduction of religious education into school.

SdRP, SDU and some other socialist and social-democratic parties had formed the original Democratic Left Alliance as a centre-left coalition just prior to the nation's first free elections in 1991.

After the elections, the coalition was joined by the Polish People's Party (PSL) in forming a government and Leszek Miller became the Prime Minister.

By 2004, the support for SLD in the polls had dropped from about 30% to just below 10%, and several high-ranking party members had been accused of taking part in high-profile political scandals by the mainstream press, including the Rywin affair, in which film producer Lew Rywin, claiming to be acting on behalf of the government, sought a bribe from the editor of the Gazeta Wyborcza newspaper in return for favourable amendments to a proposed new law on media ownership.

Prime Minister Leszek Miller was obliged under Polish law to report the attempted bribery to the police when it was brought to his attention, but did not do so.

[15] After the elections, one of the party members, Sławomir Kopyciński, decided to leave SLD and join Palikot's Movement.

[23] The SLD is usually seen as the face of the standard Polish left, having achieved notable electoral success during the 90s and benefitting from a strongly organized network of local offices, which span 320 of Poland's 380 administrative counties.

For this reason, it was often viewed as the go-to party for left-leaning Poles for the majority of Poland's modern history.

[26][27] Besides self-described left-wingers, the party enjoys the support of many members of the country's police and military, but its largest voting bloc resides among former PZPR members, government officials and civil servants during the PPR period, which are seen as the party's core supporters.