The aim of the article is to explain the institutional development of the parliamentary scrutiny systems in Germany and the UK on the basis of existing Europeanization frameworks. So far these attempts have con-centrated on policy specific analyses or on the development of governmental or administrative structures. There has been no attempt to explicitly link the evolving discussion on the role of national Parliaments and the development of scrutiny structures to the theoretical debate about Europeanization and domestic change. We will apply a strict top down approach taking on board key notions of the Europeanization literature such as misfit, mediating factors or domestic change. However, in order to grasp the various dynamics at work we had to specify the existing frameworks. The rather undefined concept of 'misfit' between the European and national level is divided into three sub-categories: constitutional, functional and cultural misfit. This allows for a more differentiated analysis of how the various mediating factors exerted their influence on the development of the domestic institutions. Drawing on explanatory models from sociological as well as ra-tional choice institutionalism we argue that cultural factors such as the attitude towards European Integra-tion account for the longer term developments of the scrutiny systems whereas formal mediating institutions such as national Governments or Courts are responsible for the more abrupt changes.