In recent years, European networks of national regulators and supervisors have emerged in a variety of policy fields. These networks are seen as a way to coordinate national implementation and enforcement of EU legislation in situations where centralization of these activities at European level is undesirable or politically infeasible. This article explores whether such networks indeed lead to a higher level of coordination between the member states. The authors do so by comparing four directives (two in the field of financial market supervision and two in the field of environmental policy) the implementation of which was coordinated within European networks. The results of this study show that coordination is strongest for those directives where the interdependence between national supervisors is greatest and national supervisors thus have a direct interest in coordination. This implies that European regulatory networks are only an effective form of coordination for issues involving strong interdependencies between national supervisors.