Communities of practice have been identified as playing a critical role in the promotion of learning and innovation in organizations. Yet, while innovation may be facilitated within communities of practice, radical innovations frequently occur at the interstices across communities. Here the perfomative advantages of communities of practice are less clear. Moreover, while it has been suggested that managers play a critical role in constructing, aligning or supporting communities of practice, there is little empirical evidence for these assertions. This article contributes to these debates on the construction of communities of practice and their role in the innovation process. It does this through a case study of a radical innovation for the treatment of prostate cancer. The case focues on Medico - the company that manufactured a product for the new treatment - and explores attempts by managers to contruct a new `community of practice`as a vehicle for innovation. While the case highlights attempts by managers to construct communities as `social objects' it also underlines the shift in management strategies and practices associated with such a construction. Faced with powerful professions, and limited organizational support, managers employed a strategy centred on constructing a community focused on the disease ( rather than the product) using `community of practice`as a rhetorical device to enrol key professionals and to mobilize and legitimize changes in work practice. Thus community building reflected managers'lack of power to intensify innovation by other means