 When on 23 January 1920, the regulations of the Treaty of Versailles became effective, and the Polish Corridor was arranged in a newly reborn Polish state (Second Polish Republic), Graudenz was incorporated under its Polish name Grudziądz into the new Second Polish Republic, although a majority of inhabitants of Grudziądz were German.At that time Józef Włodek, the newly appointed Polish mayor, described his impression of the town as "modern but unfortunately completely German"

Between 1926 and 1934 the number of Germans (34,194 in 1910) rose from 3,542 to 3,875.Some Polish authors emphasize a wider emigration pattern motivated chiefly by economic conditions and the unwillingness of the German minority to live in the Polish state.