Abstract. This paper analyses the emergence of public sector international joint laboratories as an increasingly important new phenomenon in the internationalisation of public sector research. Using a survey and interview-based qualitative methodology, it explores the trends in the establishment of such laboratories, the aims for which they are established and the extent to which these aims are met. We find a considerable degree of organisational diversity among them in terms of size, structure, resources and legal status. Since the French Centre National de la Recherche Scientifique and the German Max-Planck-Gesellschaft have been very active in setting up joint laboratories, the paper undertakes two case studies of the instruments of these organisations based on the background literature and in-depth interviews. We argue that their joint laboratories are examples of the institutionalisation of the dymanics of previously self-organised international collaborations and that they have developed these international collaborations to achieve specific organisational goals.