January 1, 2013 have passed twenty years since the formal establishment of the single internal market of the European Union. This does not mean that from that day there were no barriers to movement of goods, persons, services and capital. They were abolished gradually, but still today the European Union’s internal market, which consists of 28 countries and inhabited by over 500 million people, it does not operate as a single national market. The aim of the study is to show the evolution of the functioning of the free movement of goods, persons, services and capital, with particular emphasis on the direction of changes in the near future.