The thesis deals with the analysis of the Croatian pension system in the environment of the EU. The structure of the thesis is divided into five parts. In the first part, the reader is introduced to the subject area, after which the beginnings and foundations of pension insurance in the Republic of Croatia are discussed. In the third part, the Croatian pension system is analyzed, and in the fourth part, the pension systems in the European Union. In the last part the conclusion is drawn and at the end of the paper it is bibliography, tables and graphs. The thesis states that most of the European Union member states, including the Republic of Croatia, are facing negative demographic trends such as declining birth rates, emigration and aging of the population. These trends have an impact on the pension system, as they lead to a decreasing number of insured persons and a larger number of pensioners, which calls into question the sustainability of pension systems. With contribution rates and tax levels close to their maximum in most member states, the main solution to the problems caused by demographic change is to promote employment in the labor market. Of course, the problem could also be solved with good population policies. It has also been noted that the adequacy of pensions in the Republic of Croatia is very low and that Croatia lags behind the European Union average in all major adequacy indicators. For this reason, the following changes and reforms of the pension system of the Republic of Croatia should be urgently considered.