AbstractTo what extent is an increased stringency of the Intellectual Property Rights (IPR) system apt to stimulate research cooperation between developed and emerging economies? To address this question, we empirically investigate how international joint research projects in the pharmaceutical sector are affected by the regime of IPR in force in the two countries involved in the collaboration. Looking at the joint signature of both patent documents and scientific papers by researchers located in developed and emerging markets, our investigation indicates two opposite effects: joint publications are fostered by stricter IPR rules, whereas joint patents are discouraged. A recently proposed theory provides a plausible rationale for this apparently contradicting result.