The dynamics taking place within the political system means that changes take place in it. The Polish political system is not an exception in this respect – in the period 1989–2019, it is possible to indicate numerous examples of modifications of political institutions. However, relative-y rarely we have to deal with changes that are so thorough that they contribute to a significant strengthening or weakening of the body’s political position. An example of such trans-formations is the National Assembly of Poland, which periodically had such competences as the right to choose the president of the state or the right to prepare and enact the Constitution of the Republic of Poland so important to the political system. Currently, this body is activated only when working on its own regulations, an oath made by the President of the Republic of Poland, and when the celebration of the jubilee presupposes the proclamation of the ad-dress by the President of the Republic of Poland. This study is an analysis of the evolution of the National Assembly of Poland in connection with the changes taking place within its competences, it is also to allow answering the question about the rank of this body in the future.