This paper discusses the extent and the determinants of the internationalization of European inventive activity, between 1990 and 2004, using an innovative method to treat the information contained in the European Patent Office's Patstat database. The observed level of internationalization of inventive activities, while being rather low, has steadily increased over time. The amount of collaboration between actors residing in different countries is assessed by means of a "gravity model", as it is familiar in the literature on international trade. The amount of bilateral collaboration is positively affected by the presence of a common language and a common border, and by the common participation in the European Union. Participation in the Euro Zone is also found to have a (marginally) negative effect. International collaboration is negatively affected by distance, with estimated elasticities that are significantly smaller than the ones that characterize international trade. Contrary to the rumors about the "death of distance", this effect has become stronger in recent years.