This paper intends to verify the impact of geographical proximity on the processes of knowledge acquisition and exploitation by high-tech start-ups considering at the same time the role of both the social and cognitive dimensions of proximity. Our basic assumption is that proximity means a lot more than just geography. The findings from this research broaden our understanding of how start-ups located inside an industrial cluster acquire knowledge from their customers and exploit it in an innovative way, underscoring the need to reconsider assumptions regarding the importance of geographical proximity between business partners during knowledge management.