The Social Democratic Workers' Party in Subcarpathian Rus' was a social democratic political party in Carpathian Ruthenia in Czechoslovakia. The party was founded in 1919. At the party congress in September 1922 the party adopted a party programme which acknowledged the inclusion of Carpathian Ruthenia as an autonomous region in the Czechoslovak Republic. The party obtained the support of the Gregory Žatkovich, the first governor of Subcarpathian Rus, during his tenure 1920–1921.