The party system and the parties within it were ones of the relevant elements of system transformation in Poland. We can identify several significant determinants of the process with regard to this area. The first of them is formal standards and their influence on the course of political competition. The second is the functions attributed to political parties in the political and party system. The third one is connected with the significance of social structure’s specificity and its influence on voting behaviors. The fourth determinant is the models of competition at the cabinet level. The paper presents these four determinants of development of political parties and the party system in Poland in the perspective of democratization processes.