In this paper we outline a theory of care transition. Under conditions of demographic and epidemiologic transition, combined with rising costs, new forms of health care develop. This process is summarized as a shift from medical dominance to managed consumerism in an ageing society, involving significant changes in the nature of professionalism and professional practice. An emphasis on professional regulation and evidence-based practice, combined with partnership, shared decision-making and concordance is found in a range of policies aimed at altering the social relations of health care. Choice, self-management and active engagement in health become features of a restructured patient role. The paper concludes by suggesting that further work needs to be carried out to test whether these ideas for a theory of care transition can be applied more generally.