The Ukrainian Social Democratic Labour Party (Ukrainian: Украї́нська соціа́л-демократи́чна робітни́ча па́ртія) was the leading party of the Ukrainian People’s Republic and was also known as SDPists or Esdeky. The party was reformed in 1905 at the Second Congress of the RUP and was pursuing the Marxist ideology. The leaders of the Ukrainian Social Democratic Party were Volodymyr Vynnychenko Symon Petliura Mykola Porsh Dmytro Antonovych Lev Yurkevych Mykhailo Tkachenko M. Kovalsky.
