One of the motives for the emergence of economic integration, ie the EU, is the freedom of movement of money, and in order to further simplify it, a monetary union, ie European Monetary Union (EMU), was formed. The obligation of the Republic of Croatia as one of the EU members is to join the EMU, but for the application of the euro it is necessary to meet certain conditions (convergence criteria) that are set before the Republic of Croatia. The problem of this paper can be defined as ignorance of the advantages and disadvantages that arise for an EU member since joining the EMU. The aim of this paper is to present the potential advantages and disadvantages of joining the EMU that may affect the Republic of Croatia since joining the EMU. The theoretical part of the paper defines economic integrations, because the European Union is the highest level of economic integration in terms of the intensity of integration and as such the only example in the world. The history and development of the EU and EMU are defined in order to show the advantages and disadvantages of EMU membership. It can be concluded that the advantages of EMU membership are numerous, while the disadvantages are the cost of adjustment and the loss of decision-making autonomy related to monetary and fiscal policy. In addition, it can be concluded that the advantages and disadvantages reflect differently on the EMU Member States depending on their characteristics, the most important of which is the level of economic development.