This paper addresses the strategies adopted by science-based start-ups to gain access to knowledge resources at different spatial levels. The goal of the paper is to investigate the presence and relative importance of ties endowed with different types of proximity in firms’ knowledge networks, as well as the role played by non-geographical proximity in gaining access to knowledge sources, both located nearby and at a distance. For this purpose we develop an analytical framework that permits to distinguish between two dimensions of proximity: geographical, associated with the spatial location of the actor; relational, associated with the origin of the tie – leading to different modes of proximity that are further linked with modes of knowled...