The thesis informs a reader about problems of establishing new/small political parties and their activities in Czech Parliament during the period of 2002 -- 2010. The surprising and unexpected results of Chamber of Desputies election that took place in May 2010 and brought considerable transformation of contemporary political establishment in Czech republic, represented the main impulse for writing this thesis. The aim of the thesis was to find out the size of political market openness for new/small political parties during the period of 2002-2010 and simultaneously evaluate what kind of position and substance these new/small political subjects in the political market have. A content of thesis is divided into two main parts. The first part is focused on theoretical theme and includes four chapters. There are mentioned mainly the issues of new/small political parties' definitions, the role of relevant parties in proportional representation systems and also some of the most important attempts of electoral reforms. The second part includes the final chapter that is focused on analysis of the factors that had influence on increase or decrease in chances of new/small parties to be successful in Chamber of Desputies elections from 2002 and thus become the part of political establishment. The fundamental questions were: How have the new/small political parties built up in that period of 2002-2010 and under what circumstances have they become the part of political establishment.