Croatian Spring is the national reform movement led by croatian political, student and humanist representatives during mid 60’s and early 70’s of 20th century with the purpose of democratization, liberalization and realization of related rights of Croatia in the borders of existing Yugoslavia. Unequal position in economic, political and social life of the FR of Croatia in FR of Yugoslavia led to awakening of national identity and first clear movements in fighting for democratization of society. Resignation of Aleksandar Ranković in 1966 was recognized as good opportunity for the change of claim unitarist and centralists politics of past political leadership. In 1965 Economic reform was carried out and two years later “Declaration on the Status and Name of the Croatian Literary Language” was published. With publication of Declaration in weekly Telegram began the fight for position and rights of Croatia in Yugoslavia and new path of national identity awakening was initiated. The political top of the communist party in Croatia increasingly animates reforms within Yugoslavia. Students, almost unanimously, join the requirements and support KPH leadership overtly. Given that the awakening of the national identity and the call for democratization in these moments are seen as danger for the political system and the survival of the FR Yugoslavia, gradually comes to calculation with all important persons of the Croatian Spring. Leading political factors are forced to resign, students are sentenced to imprisonment and intellectuals are removed from public and social activities. The essence of the Croatian Spring was, however, achieved through the constitutional changes in 1971 and by introducing 1974 Constitution when political system was democratized and republics gain right to self-realization and disengagement. This kind of political solution for the most part satisfies demands of the National Reform Movement and creates an unequivocal legal basis for the independence and autonomy of the Republic of Croatia two decades later.