Much evidence exists of the increasing levels of research cooperation and globalization in the knowledge generation process. This paper aims to assess the determinants of the quality of research collaborations, using a sample of joint patent applications to the European Patent Office between 2000 and 2012. The results of the empirical analysis show that the limited exhaustibility of knowledge and the geographical distance among research partners are crucial determinants of research quality. Specifically, the non-exhaustible character of knowledge and cross-border knowledge creation enhance patent quality. Moreover, the distance among research partners exerts a curvilinear effect, as the quality of innovation increases when partners are either in spatial proximity or distant among each other.