In this paper, the main topic is related to the introduction of the euro as a national currency in the system of the Republic of Croatia. The paper will address issues with countries that have introduced and those that are only now in the process of introduction. The Republic of Croatia has been a member of the European Union for seven years but has not yet adopted the euro as its currency, but is making every effort to meet the conditions and introduce it as soon as possible, ie is not yet able to adopt the euro until it meets all Maastricht criteria. With the introduction of the euro, many experts believe that there will be easier trade, reduced fees in trade as well as in the payment system. A major problem is the Croatian economy, which is weak and unable to accept certain changes and conditions required by the introduction of the euro. Monetary policy should primarily be non-interventionist, but the state solves the problem of financing its expenditures and deficits with this policy, which will certainly have consequences for the state. When the economy is in full employment, it is necessary to pursue a restrictive monetary policy to prevent price increases. For this reason, monetary policy is recommended when the economy is in a favorable position, ie in a state of prosperity. On the other hand, when the economy is in recession, fiscal policy is recommended, because expansive fiscal policy affects the growth of consumption and demand, which is one of the conditions for the economy to emerge from recession. This use is also influenced by the statement that monetary policy has greater effects in the long run, ie its effects spread more slowly, so it is used in a period of prosperity in which the economy wants to be as long as possible. The paper will define the importance of the common monetary policy of the European Union, but will also analyze the benefits of the introduction of the euro as a currency in certain countries.