This article explores John Dewey’s theories of inquiry, communication and existence in relation to design inquiry or, more particularly, research which incorporates design practice. Held in combination, these theories are seen to offer a unique approach to knowledge. This approach, it is argued, can be readily appropriated within existing methodological formulations of design research. By way of demonstration, I conclude the article by outlining a number of key features of Dewey’s theories, which are seen to hold the potential to enrich the epistemological basis of design inquiry as a research approach.