The care of frail older people and their family carers present significant challenges for welfare systems throughout the world. In order to address their needs, policy initiatives are promoting partnership working between service users, family carers and providers, whereby the former are increasingly involved in the design and evaluation of services. However, participatory models of working raise fundamental issues about power relations and pose important questions about what constitutes ‘evidence’. Several authors identify tensions between movements such as evidencebased practice and initiatives designed to increase the active participation of service users suggesting that there is a need for a new approach to research that reconciles potentially conflicting goals. This paper describes the evolution of a model of participatory research resulting from a collaboration between Sweden and the United Kingdom, which actively involved older people, family carers, service providers and voluntary organisations. The model is underpinned by constructivist principles that have been adapted by the authors so as to be more intellectually accessible to a nonacademic audience. The conceptual basis for the model is described and a case study illustrates how it is applied in practice. It is argued that the approach could be adopted widely as a means of more fully engaging older people, their families and a range of service providers in important debates about future health and social care provision.