The first attempt to outline a path of economic and monetary union in three stages over a period of ten years, begins in 1970 with the report WERNER 1. However, this initial project did not come to fruition as a result of strong tensions that describes exchange currencies in international markets after the collapse of the Bretton Woods system in the early 70s, as well as the economic recession caused by the oil crisis in 1973. To cope with this situation fragile and unstable, nine member states of the EEC in 1979 created the European Monetary System (EMS), which basically was the mechanism of the exchange rate (MCR). This mechanism is provided for these 9 countries currencies, the determination of an exchange rate regime fixed, but adjustable. The idea of EMU will rejuvenate the Single European Act in 1986, which created a common market. This milestone also brought the conviction that the full benefits of the common market only if it can yield the participating countries will st use a single currency. In 1988, the European Council Delors Committee appointed to examine the possibilities and avenues for the creation of Economic and Monetary Union (EMU). A year later, the Delors Report will open the way to negotiations on the European Union Treaty, which created the European Union (EU) and thought the Treaty establishing the European Community. Otherwise known as the Maastricht Treaty, because the town where it was signed in February 1992, the Treaty of the European Union came into force on 1 November 1993. Road to EMU in Europe passed through three stages: The first phase (1990-1993) was characterized by the establishment of a common European market through the removal of all internal barriers to the free movement of persons, goods, capital and services within Europe. The second phase (1994-1998) began with the creation of the European Monetary Institute and focused mostly on the technical preparations for the European common currency, to avoid higher deficits and convergence of economic and monetary policies of the Member States (for sigruar price stability and sound public finances). The third phase began on January 1, 1999, with the irrevocable fixing of exchange rates, the transfer of powers of monetary policy to the European Central Bank (ECB) and the use of the euro as a single currency. On 1 January 2002, euro banknotes and coins were put into circulation in the participating countries and the end of February 2002 national banknotes and coins are no longer legal tender rejoiced. Today, after almost 12 years in circulation casting the single European currency and after the economic crisis of the euro area, which appeared in all its forms naturally arises: Euro has brought more costs or benefits? So, this paper aims to bring an analysis of the costs and benefits of the common currency Euro. DOI: 10.5901/ajis.2014.v3n6p67