104 страниц. 2010 год. LAP Lambert Academic Publishing The presetn work aims at exploring how proximity dimensions can favour the diffusion of knowledge between economic actors, focusing on the knowledge relationships established by a knowledge gatekeeper. In particular, I formulate several hypotheses regarding the role of geographical, organizational, and technologicalproximity dimensions in affecting the establishment of gatekeepers’ knowledge relationships, taking into account their collaborative-non collaborative type and exploitative-explorative nature. Hypotheses are tested on a sample of 527 knowledge relationships established by two distinct types of knowledge gatekeeper, i.e. a multinational company and a university. In particular, they are the Technical University of Milan and the ST Microelectronics Italy, which represent the Italian university and firm best performing as knowledge gatekeeper.