The debate on the entrepreneurial university has raised questions about what motivates academic scientists to engage with industry. This paper provides evidence based on survey data for a large sample of UK investigators in the physical and engineering sciences. The results suggest that most academics engage with industry to further their research rather than to commercialize their knowledge. However, there are differences in terms of the channels of engagement. Patenting and spin-off company formation are motivated exclusively by commercialization whilst joint research, contract research and consulting are strongly informed by research-related motives. We conclude that policy should refrain from overly focusing on monetary incentives for industry engagement and consider a broader range of incentives for promoting interaction between academia and industry.