The freedom of movement of workers is one of the four fundamental freedoms on which the internal market of the European Union rests. From an economic and social point of view, the freedom of movement of economically active individuals - workers, is important for achieving the goal of the European Union, which is the creation of a single market of all member states. The freedom of movement of workers is regulated by primary and secondary legislation, and a special role in the interpretation of provisions is given to us by the Court of the European Union. By defining the term "worker", the Court prevents national definitions from being misused. The principle of equal treatment gives foreign workers equality in terms of employment and employment conditions compared to domestic workers. The freedom of movement of workers can be limited for reasons of public order, public safety and public health, and judicial practice shows us that the stated justifications for the restrictions were a source of abuse, so the Court of the EU in its judgments gives a clear interpretation when such a restriction is possible: when personal behavior the individual must represent a serious, real and present threat. In order to preserve the unity of the worker's family, a Directive was passed for this purpose, which also grants certain rights to the members of his family, taking into account the dependency relationship between the worker and the family members. The freedom of movement of workers encourages the migration trend, which seeks to improve the living conditions of the workforce.