Proportional electoral system has been implemented in the Croatian legislation since electoral reform from 1999. The main purpose of this reform was to achieve the principal of stability and the principal of justly parliamentary representativeness of all social groups. In order to enhance these results, Hrvatski sabor (national parliament) has implemented a law that has brought up a new division of 10 electoral constituencies which were widespread over the territory of Republic of Croatia. Despite of -/+5% legally allowed deviations in a number of registered voters among electoral constituencies, we are witnessing a growing number of constituencies which have deviations over 5%. These deviations lead to violation of a constitutional rights of citizens because the Constitution of Republic of Croatia proclaims equal voting right for all Croatian citizens. The Constitutional Court of Republic of Croatia is also familiar with this problem and it has reacted towards to national parliament to solve this irregularity. Alongside with a high elective threshold and D'Hondt method for seats allocation, unequal voting power causes most of the negative effects of the current electoral system. While high electoral threshold and D'Hondt method draw its legitimacy from Croatian electoral law and European electoral tradition, unequal voting power breaks legal norms of electoral law which are implemented in order to ensure a compliance with constitutional equal voting rights. Accordingly, unequal vote power represent the most serious problem of the Croatian electoral legislation and in this paper it will be explored to what extent it affects the Croatian electoral system.