The paper aims to analyse various aspects of interdependence between the nationality and the citizenship of the residents of Klaipėda region by restricting the analysis to the political and economic factors of the 20th c. The analysis was carried out on the basis of little known archival materials. The article seeks to prove that nationality and citizenship, as the principal forms of the identity expression, have not always been a matter of free self-determination; they would frequently change depending on the external political and ideological pressure.