Constitutional law represents the basis of the legal order of a country and the key values on which the country was built. The aforementioned branch of law cannot be separated from the political system of the state, because the Constitution regulates political issues and the complete system of institutions at the level of one state. In modern constitutions, exceptional emphasis is placed on the protection of fundamental human rights and freedoms, and the Constitution defines the organization of state power as well as the manner of conducting elections and referendums. The paper describes the process of adopting the Constitution of the Republic of Croatia from December 22, 1990, which is specific because at that time Croatia was still a formal and legal member of the SFRY, and explains the individual constitutional changes and the reasons why they were implemented. The structure of the Constitution of the Republic of Croatia is also described