This paper aims at investigating the role of different types of proximity on the technological activity of a region within the context of a knowledge production function where R&D expenditure and human capital are the main internal inputs. We intend to assess if, and how much, the creation of new ideas in a certain region is the result of knowledge flows coming from proximate regions. In particular, we examine in detail the concept of proximity combining the usual geographical dimension with the institutional, technological, social and organizational proximity. The analysis is implemented for an ample dataset referring to 276 regions in 29 European countries (EU27 plus Norway, Switzerland) for the last decade. Results show that human capital and R&D are clearly essential for innovative activity but with an impact which is much higher for the former factor. As for the proximity and network effects, we find that geography is important but less than technological and cognitive proximity. Social and organizational networks are also relevant although their role is modest.