There are two fundamental approaches to the concept of constitution, as the highest legal act of constitutional law defining the predominant number of norms, laws and regulations. Constitution in material and formal sense. In most states, statutory regulations, acts and constitutional norms are in written form. The unwritten constitution is a set of constitutional customs that exist in a particular country. In rigid constitution, norms are above statute and can be changed in a way that differs from law adoption and change. Change to the flexible constitutions is possible in the same way that laws are changed. Deciding on applying the law in accordance with the Constitution is in the domain of Constitutional Courts. The Constitutional Court of Republic of Croatia was constituted by the 1963 Constitution of SRH, as the Constitutional Court of Croatia and began to work on February 15, 1964, after the Law was passed in the Constitutional Court of Croatia in January 1964. It had the authority to evaluate the constitutionality and legality of the self-managing general acts (the jurisdiction to decide on the constitutionality and legality of individual acts was almost non-existent). This was amended by the provision of the Constitution of the Republic of Croatia of 22 December 1990 published in NN, no. 56/90. Constitutional judicature in the wider sense is the protection of constitutional law in order for the state to function in accordance with the Constitution. In the narrow sense, it is the examination of the constitutionality of the law by the court. It can only be done in the system of the rigid Constitution. The purpose of constitutional judicature is depoliticization. In order to avoid it, jurisdiction is given to the court that enforces it on the basis of constitutional norms. Constitutional judicature in the territory of the Republic of Croatia can be divided into two time periods. Constitutional judicature from 1963 to 1990, in which Croatia was one of six federal units (republics) within the former SFRY and constitutional judicature in the Republic of Croatia from 1990 until today.