The work consists of 3 units in explaining the cause of public debt in the case of Croatia. In the first two parts there is theoretically explained topic, and in the last part is used by practical work in which the objective is to analyze and explain the concept and importance of public debt to macroeconomic stability and economic growth. The theoretical part explains the public debt as a concept and its importance. In the second part is explained about the causes of trends and structure of public debt of the Croatia. With this comparison is made Croatian and post transition countries in order to compare the significance and consequences of public debt, and analyzes the determinants according to previous studies that were used in the further processing operation. In the last general statistical method is used by multiple regression of Croatian public debt as a model to identify the determinants of public debt. According to the research results it was concluded that the impact on public debt movements have unemployment rates and the rate of growth of government spending to GDP. Additional analysis using the established trend of variables shows that still greater impact on public debt movements have unemployment rate compared to the growth rate of government spending to GDP. Weight selection determinants of public debt is a complex structure of public debt as a concept that has a very broad impact on the economy and stability.