In this study, an analysis of the spatial characteristics of collaboration in scientific knowledge production in the Netherlands is performed. Within science-based industries, collaboration between governmental, academic and private organizations in scientific knowledge production is an important and growing phenomenon. Based on theoretical insights from the literature of the geography of innovation it was hypothesized that collaborations between organizations with different institutional backgrounds were more regionalized than collaborations between organizations with the same background. Co-publications in scientific subfields that are relevant for technological innovation in semiconductors and biotechnology were used as a proxy for collaboration between organizations. The main finding of this study is that heterogeneous collaborations are more regionalized than collaborations between the same kinds of organizations. Even after controlling for the spatial distribution of universities and the dominant position of Philips within the semiconductor technology in the Netherlands our hypothesis is confirmed. This can be seen as empirical evidence for the importance of geographical proximity for successful collaboration between organizations with different institutional backgrounds, like universityindustry collaboration. Geographical proximity does not seem to play an important role for collaboration in science between organizations with the same institutional background. Homogeneous collaboration occurs relatively more at the international level, thereby indicating that institutional proximity is more important here than geographical proximity. Also these results illustrate the fact that science takes place in international epistemic communities centred around a global discourse.