The Author assumes that the liberalization of the services in the Eu has a direct impact on national labour law. This thesis is illustrated, on one hand, clarifying the concept of "service" in the Ec Treaty and in the Italian legal system. On the other hand, the essay underlines as, in many cases, the provision of services is characterized by a labour intensive nature. In this sense the cross-border service provision makes the transnational workers mobility (posting) possible but, at the same time, it affects legal and contractual provision concerning employment conditions applicable in the host Member States. Finally, it is highlighted how the development of the internal market for services may generate risks of social dumping and regulatory competition among Member States.