This study deals with the question of crisis in the Polish Socialists Worker's Party in the Czechoslovak part of the Teschen Silesia in the years 1934 and 1935. In 1934 Poland arranged a pact on non-aggression with the Nazi Germany. The Polish diplomacy then started sharp propagandist campaign against Czechoslovakia, under the pretext of the Czechoslovak persecution of the Polish minority in the Czechoslovak part of Teschen Silesia. This situation put the Polish socialists in the Czechoslovakia before the dilemma, whether keep the loyalty towards their Polish ethnicity, or towards Czechoslovak democracy, because the ruling regime of so-called 'sanacja' in Poland was authoritative and undemocratic. The aim of this study is to show, how Polish socialists deal themselves with this dilemma. At the preparing of this study were mainly used materials from the Land Archives in Opava, the Moravian Land Archives in Brno, the National Archives in Prague, in the Polish institution 'Biblioteka Slaska' (the Silesian Library) in Katowice and from the press of that time.