This article aims at contributing to the understanding the connection between trust in political leaders and institutions and legitimacy of power under conditions of societal transformation. Basing on the sociological monitoring data of the Institute of Sociology of the National Academy of Science (NAS) of Ukraine "Ukrainian society 1992-2012" and European Social Survey 2005-2011 the authors have come to conclusion concerning the necessity of creating a model which would consider the specific social and political features of post-Soviet countries and all factors influencing the process of legitimacy. The authors have also concluded that the level of confidence in political leaders and state-political institutions is one of the crucial indicators of legitimacy.