This paper will address the topic entitled: “ Costs and benefits of the accession of the Republic of Croatia to the monetary union”. The European Economic and Monetary Union as well as the convergence criteria are analyzed. The example of Slovenia and Greece shows that after joining the European Monetary Union, the advantages and disadvantages manifest themselves differently, depending on the situation in the country. The question is how these advantages and disadvantages will affect the Croatian economy and whether the benefits of accession will ultimately outweigh the costs. The introduction of the euro would eliminate currency risks within the economy, and successfully to reduce borrowing costs and reduced the risk of the outbreak of the banking crisis. There would also be lower transaction costs and encouragement of international trade and investment. It also provides the opportunity to participate in the distribution of monetary income and access financial assistance mechanisms. Disadvantages include one-off conversion costs, the transfer of funds to the European Central Bank, participation in assistance to other Member States and the risk of price increases due to conversion. There are also disadvantages permanent loss of monetary policy and the risk of excessive capital inflows and the accumulation of macroeconomic imbalances.