The particular attention in the paper is paid to the analysis of evolution of party system of Kenya from its pre-independence stage to current situation. Key significance of the ethnic factor in the Kenyan politics is disclosed including its implications in the Constitution of Kenya. Central part of the paper is devoted to the details of the transition from the one-party authoritarian regime under Presidents Jomo Kenyatta and Daniel Moi to the multiparty democratic political process under Presidents Mwai Kibaki and Uhuru Kenyatta. Some light is shed on the role of political opposition in the establishment of current political system of Kenya and also on the specific features of Kenyan party system development. Extreme importance of ethnic mobilization in the electoral process as well as in the functioning of the main governmental institutions is stressed. Current political situation in the country is described in the final part of the paper.