Many current economic theories on innovation hold that individual firms are seldom capable of innovating independently and that the search for new product and process ideas goes beyond the firm?s boundaries to other firms or institutions (Cassiman and Veugelers, 2006; von Hippel, 1988). This idea has been embraced by the recent open innovation literature, which assumes that firms can and should use external knowledge sources for their innovation processes (Chesbrough, 2003; Laursen and Salter, 2006; Leiponen and Helfat, 2010). However, despite the number of studies carried out on this topic, the results related to the effect of external knowledge sourcing strategies on firms? performance is controversial, especially when its joint effect with internal knowledge generation is considered. In this sense, there is still a need for further theoretical and empirical research regarding to the factors that influence the firm´s capacities to acquire and exploit external knowledge for innovations. This project aims to contribute to this field by analysing, theoretically and empirically, how organizational dimensions of the firms (organizational structure and management practices) shape its external knowledge sourcing processes. Specifically, the project will address the following questions: 1. How do organizational structures and management practices influence in the configuration of knowledge sourcing processes? 2. Do organizational structures and management practices influence in the effect of knowledge sourcing processes on firm performance?