The article outlines the history of Poland’s participation in international organisations spanning almost 100 years. It primarily sets out to identify and assess the specific issues regarding national sovereignty that boasted key pertinence throughout that time. It focuses on the three periods, i.e. the interwar period, marked by Poland’s membership in the League of Nations, as well as by coercion to undertake a certain scope of international obligations, Cold War period – the time of “limited sovereignty” and subordination to the Soviet Union, and the last one, i.e. following the end of Cold War, and the change of a political system in the country. It was in that time, in the environment of growing interdependence and deepening international integration, accompanied by major changes within the scope of membership in international organizations, that optimum political positions and relations within the fold of those organizations had to be worked out in terms of the country’s vital interests, which would not have been possible without maintaining its sovereignty in the first place, while also having it subjected to a major rethink, with a view to its ultimate redefinition.