In the past few years the effects of European integration on national legal and administrative structures have increasingly attracted the attention of legal and administrative analysts. One of the main topics of this branch of research based on the catchword 'European isation' is the question whether and to what extent these processes have led to the approximation of national legal and administrative structures in the course of time. However, we still lack comprehensive findings as to whether and under what conditions the effects of European integration lead to domestic administrative and legal changes. It this paper, we try to address this research gap. We analyse whether and to what extent the implementation of European policies leads to an approximation of legal and administrative structures in the Member States. This question will be thoroughly elaborated by using the example of the implementation of directives related to the Environmental Impact Assessment (EIA) and the Strategic Environmental Assessment (SEA) in Germany and England.