The euro area today consists of 19 relatively very different member states, and these differences especially come to the fore when countries are classified into 2 clusters: core and periphery. In currency unions such as euro area asymmetry occurs in several respects, so the heterogeneous structure of member states and their level of convergence (divergence) must be taken into account in conduct of macroeconomic policies, but also the asymmetry of economic shocks and countries' responses to those shocks. Regardless of the type, shocks are not symmetrically distributed within the euro area. In the absence of other common measures and policies, monetary policy has emerged as an instrument to address imbalances. However, its ability to stabilize economies is limited due to the asymmetric nature of shocks and other heterogeneities, and its effectiveness is questionable in an asymmetric and heterogeneous environment such as the euro area. Target economic variables in different countries react differently to monetary policy measures and instruments, resulting in a positive effect on some countries and a simultaneous negative effect on other euro area member states. Therefore, the ECB must simultaneously take into account the existing asymmetries within and between member states and the potential asymmetric effects of the transmission of its own monetary policy. Monetary policy measures can correct some of the imbalances, but monetary policy should not be expected to address those problems and imbalances that it cannot influence or correct. Given the entry into the ERM II exchange rate mechanism and the imminent introduction of the euro as the national currency, this topic is also important from the aspect of the Republic of Croatia. Certainly, the character and measures of the ECB's monetary policy will not always correspond to the current economic situation in Croatia due to the fact that the ECB's monetary policy is more significantly influenced by economic trends in the core countries. The global financial crisis and the debt crisis of the europeriphery have reversed monetary trends in the euro area, led to the introduction of unconventional monetary policy measures and stressed the importance of macroprudential policy.