The quality of contemporary residential development, and the associated design challenge for house builders, are important current policy issues in England. Until recently, better-designed contemporary housing development was more frequently seen on smaller, more constrained urban or brownfield sites and more rarely on greenfield sites. Set against a significant shift in the prevailing planning regime during the 1990s (from greenfield development to an express policy emphasis on brownfield development), this paper attempts to explain this observation. Utilizing the concept of ‘opportunity space’, it develops a model of the role of design and the designer in the development process, which is then used to account for differences in the quality of development on greenfield and brownfield sites. It is suggested that the development of greenfield and brownfield sites displays significant contrasts and that, as a consequence, successful brownfield developers yield opportunity space in their business strategies to designers.