Thesis consists of four parts where the first three parts of theoretical, and the last is the one empirically where it comes to the main conclusions of the analysis of the above hypothesis.The first part explains the essence of this work and the main targets. It consists of a problem and an object of research, primary and secondary objectives and methodology which will analyze the main determinants of foreign debt. Second part includes basic information about external debt starting from the idea and the most important characteristics, ie theoretical methods to complete the work. The key point of this part of the sustainability of external debt, and this part ends with the maturity and currency structure of external debt of Croatia.The third part of it is the most important part of the theoretical part of the work because it is theoretically handle major determinants that are divided into endogenous and exogenous or internal or external and analyze their situation in Croatia.Finally, the last part of the multiple regression model to prove the proposed hypotheses and shows the influence of independent variables on foreign debt or the interrelationship of some of the independent variables on the basis of which the empirical results obtained.Thesis ends with concluding remarks and explaining the results. This is followed by literature, without which this work would not exist.