The League of Communists of Croatia went through a series of changes during its existence. These reforms showed the need to listen to reactions from below. At the end of the 1980s, Yugoslavia found itself in a general political, social, economic, and ideological crisis from which there was virtually no way out. This thesis describes how the League of Communists of Croatia entered its last reform during the monopoly of power in Croatia and Yugoslavia. Intellectual and political debates in the management of LCC and other sociopolitical organizations gave rise to the concept of non-partisan pluralism, which LCC was supposed to face with a crisis of legitimacy. On this issue, the top of the LCC was divided into dogmatic and reformist currents, depending on their preference for the course and speed of change. The latter side began to prevail, largely due to increased inter-ethnic friction in the country and the authoritarian efforts of the Serbian communist leadership, so in the second half of 1989, the party press and the emerging public space began to talk more about the multi-party system. LCC decided to take this step the day before the start of its 11th Congress in December of that year. At the aforementioned congress, LCC renounced its monopoly on power and announced early multi-party elections. In the period from the 11th Congress to the elections, which were held in May 1990, LCC transformed from a mass political organization into a democratic party that competes with others for power and finally separated from the other republican parties at the 14th Congress of the Communist League of Yugoslavia in January 1990.