The central bank is the highest monetary authority within each monetary system. This is why the concern for the responsibilities, objectives and functions of central banks is present in the general economy field, as well as in those of finance, currency or financial exchange relations. Therefore, a contrasted analysis between the Eurosystem, the Federal Reserve and the Bank of Japan is of general interest for the users. The paper presents a comparison between the three systems. The status and objective differences are presented with a reference to the historical circumstances that have generated national characteristics. In the past years, due to the fact that all the three authorities have made directional changes towards independence and transparency, and because the economies of these areas are mainly convergent, a diminution of the differences between the three monetary authorities can be observed.