Business entities operating on the European market experience considerable difficulties with rendering services outside their respective countries. This is caused mainly by the necessity to adhere to local regulations whose often unjustified aim is to protect the local market from foreign competition. Implementation of the service directive and the first years of its functioning will bring an answer to the question whether the so-called Bolkestein directive (from the name of Frits Bolkestein - a former member of the European Commission) will have an impact on the process of European integration. Potentially, changes induced by the service directive can be compatible - in terms of scale and significance - to the introduction of the euro as a currency that replaced the national currencies in twelve countries of the European Union. This might be so on condition that the neo-functionalist theory of European integration proves correct and the 'spill-over' mechanism induces integration in related spheres. The presented study is a reflection on the service directive in two aspects: to what extent it can be an instrument of enhancing integration, and in what respects it is just a legal act passed to reduce a backlog.