The actions undertaken between regions to establish agreements and to institutionalize relations are a constant of the contemporary internationalorder. This article puts forward a panorama of the academic debate around the relationship between regions. The first part presents the main arguments which sustain the notion of interregionalism. The second part exposes some ideas about its analytical limits. The conclusion highlights that the analytical approach of interregionalism is in need of further refinement by empirical studies. The regional processes in America and Europe and the studies of the relationships between Europe Union and Latin America illustrate some reflections.