Mazlakh, Serhii [Мазлах, Сергій; Mazlax, Serhij], b 21 January 1878 in Ivanivka, Slovianoserbsk county, Katerynoslav gubernia, d 26 November 1937 in Moscow. Journalist and Bolshevik leader of Jewish background. He helped organize the Ukrainian Social Democratic Workers' party in Poltava gubernia for the elections to the Constituent Assembly of Ukraine and took part in the Tahanrih Bolshevik Conference on 19–20 April 1918. With Vasyl Shakhrai he wrote Do khvyli! Shcho diiet'sia na Ukraïni i z Ukraïnoiu? (1919; trans: On the Current Situation in Ukraine, 1970), which calls for an independent Ukrainian Bolshevik party and state and criticizes Vladimir Lenin’s opposition to both proposals. The authors were expelled from the Communist Party (Bolshevik) of Ukraine in June 1919, and Mazlakh was reinstated on appeal. In 1920 he became editor of the newspaper Vserossiiskaia kochegarka in Luhansk. In the 1920s he was director of the Central Statistical Administration of Ukraine (later Central Statistical Administration of the Council of Ministers of the Ukrainian SSR). He was arrested during the Stalinist terror of the 1930s, tortured, and executed.
[This article originally appeared in the Encyclopedia of Ukraine, vol. 4 (1993).]