The paper begins with an introduction and general terms related to the given topic - the Constitutional Court in the Republic of Croatia. In the second part of the final paper, he deals with the historical periods of constitutional adjudication. Originally through the period from 1963 to 1990, the socialist period, followed by the beginning of the constitutional court in the Republic of Croatia. The most important changes to the Constitution of the Republic of Croatia from 1990 onwards are highlighted. In the third part, all important items about the Constitutional Court of the Republic of Croatia, its purpose, tasks, competences and internal organization (judges) are listed. The fourth part of the paper describes Kelsen's model, according to which our judiciary operates, and compares it with the American model. The fifth and sixth parts cover the initiation of proceedings before the Constitutional Court and the exhaustiveness of the legal path leading to a constitutional complaint, which is analyzed through an example from practice.