The article is devoted to the development of the Italian economy in 1951–1973, which is recognized by researchers as the most successful period in the economic history of independent Italy, and which coincided with the first two decades of its European integration. The division of the economic history of Italy for 1951–1973 into three stages was proposed. In the first stage (1951–1957) Italy joined the European Coal and Steel Union (ECSU). Together with the admission, Italy has undertaken to change trade legislation toward liberalization, reduce quotas and tariff rates. At the same time, the Italian Government developed a program of accelerated development of some sectors of heavy industry, including metallurgy, based on the availability of cheap coal and technologies from other countries of the European Union, as well as on the emergence of promising markets for sales. The second stage (1958–1963) was reached for the first years after Italy joined the European Economic Community (EEC). This stage is known in the historiography as “economic miracle”, or “economic boom”, due to extremely high rates of economic development. It is argued that the factor of European integration has become a significant impetus for the development and transformation of Italy. As a result of the deliberate economic policy, the EEC countries have become Italy’s main trading partners. The third stage (1958–1973) is characterized by the rationalization of economic management, as well as by the gradual slowdown in economic growth. There signs of stagnation began to emerge, and they became evident after the failure to fulfil the goals of economic development of the country. A number of economic indicators demonstrate the beginning of a change in the type of Italian economy from industrial to post–industrial. However, this process had a negative impact on the pace of economic development. In general, the changes in the Italian economy during 1951–1973 were not only quantitative but also structural. Italy is an example of a semi–agrarian, under–developed country, that was in a state of post–war recovery with limited financial and natural resources, but with the help of its competent economic policy and European integration, it has become a developed industrial country, which has taken a leading place in the newly created the European common market.