Parliamentary elections were held in Poland on the 15th of October, 2023 and they changed the balance of political forces. The ruling party «Law and Justice» (Prawo i Sprawiedliwość – PiS) did not receive the necessary number of votes to form a government. The power is being transferred to the left-liberal coalition, consisting of the «Civic Coalition», the «Third Way» and the «New Left». In the article, the author made an attempt to investigate the factors that influenced the creation of a new balance of power in the Sejm. For this purpose, the course of the election campaign was studied and party documents, speeches by Polish politicians and experts were analyzed. The author concludes that the main problem for the PiS was not so much its weak result in the elections, as the lack of opportunities to create a government coalition with any of the forces represented in the Sejm. At the same time, the opposition parties were able to mobilize their supporters and rally to remove PiS from power. Their main claims to PiS are related to violations of democracy and the rule of law, and the deterioration of Poland’s relations with the European Union. These claims were heard by the majority of voters against the background of the weakening of the position of the PiS due to economic difficulties. The power passes to the coalition, although coalitions further work is likely to be accompanied by disagreements between its constituent parties