This study examines the role of university spinout (USO) companies in the emergence of a new technology, in our case nanotechnology. Three unique data-sets based on patents, co-publications, and firm data pertaining to the unfolding field of nanotechnology in the UK were developed. Subsequent analysis suggests that USOs play an important though not a dominant role. Furthermore, the results indicate that USOs in certain subfields of nanotechnology do not have a strong and growing proprietary technology base, raising questions about the commercial sustainability of these ventures. Overall, we observed that USOs are important contributors to technological change in specific subfields of nanotechnology, but that other actors, notably, large firms and (non-university affiliated) new technology-based firms are even more significant agents of technological change.