This paper provides a brief overview of knowledge diffusion theory and how it has been applied to innovation. We question whether diffusion theory is appropriate in this context and suggest that science commercialisation is a complex area for which linear diffusion approaches are neither appropriate nor effective for examining knowledge exchange between research and industry network participants. Social network analysis (SNA) is adopted and qualitative analysis is used to explore how SNA might be useful to understanding successful innovation pathways. A case study from an Australian public research organisation (PRO), the Commonwealth Scientific and Industrial Research Organisation (CSIRO), is presented to examine how a network analysis of participants can highlight the innovation trajectory taken by a biomedical product developed by CSIRO. The role of 'weak ties‘ as recruiters and key players in moving this project forward is highlighted.