Democratization is the name for a process in which arrangement of one country is transforming and goes through a transition to a democracy that involves abandoning authoritarian or totalitarian forms of government. Due to its numerous advantages that democracy offers to the state and its citizens, most countries made a transition towards democracy. Democracy begins with Athens in ancient Greece where the idea came from common decision-making of all citizens instead of the rule of the individual or elite and democracy has gradually evolved through history. The maintenance and enhancement of democracy is supported by the basic democratic principles and fundamental elements of modern constitutional democracy that are enshrined in the Constitution and the Laws. Likewise, the electoral system is indispensable for any democratic state so that citizens can choose their political representatives who are entrusted with the leadership of the country. The Republic of Croatia is one of the countries whose transformation into a democratic state through history has not taken place without any obstacles and, in addition to the political and economic transition, has faced the consequences of the war that have affected its development. One of the most important features of Croatian elections is the frequent changes of the electoral laws, and thus the electoral systems under which the elections were conducted. It is also difficult to find a country that has changed so many different electoral systems in such a short period of time. The second part of the final work is a practical part that includes a comparative analysis of the European Parliamentary Election System in the Republic of Croatia with the selected European Union countries (Slovenia, Slovakia, Belgium, Germany and Austria). A comparative analysis of the citizens' eligibility for elections to the European Parliament in 2014 in the Republic of Croatia with the selected European Union countries (Slovenia, Slovakia, Belgium, Germany and Austria) was also made. At the end of the final work in conclusion ideas were suggested for improving electoral system in the Republic of Croatia due to the current shortcomings in the electoral system.