The existing literature explains the emergence of European regulatory networks through the need for regulatory coordination and the battle for power between policymakers. Bringing together the Europeanization and policy feedback perspectives, this article suggests that European regulatory networks should also be seen as the result of a more complex process of mutual influence between the European and the national levels. An in-depth case study on the telecommunications sector reveals that the implementation of EU policies has contributed to the empowerment of national regulatory agencies, which, in turn, has conditioned the development of European regulatory networks. EU policy has thus indirectly conditioned the rise of European regulatory networks by previously transforming national administrations. Besides expanding our understanding of European regulatory networks, by bridging the Europeanization and policy feedback literatures, this article indicates promising orientations for future theoretical development in both fields.