Calls for greater community participation health-related research are increasingly made and, it seems, heeded-albeit to varying degrees. We report here, from the perspective of external evaluators, on practical efforts by the leaders of two community-based health action research projects to enhance such participation still further by employing a small number of local people as lay action researchers within their own community. 'Action research' in this context was conceived as an approach by which comparatively small projects, based on partnerships between academics, communities and public sector organisations, could address local issues of health and well-being. The purpose of the paper is to examine project leaders' initial assumptions and expectations of the lay action research role and to compare these with the actual experience of those researchers. On this basis we consider the value to organisations and communities of the lay action research role for community health development and point out some of the unanticipated risks such individuals may face. We conclude by highlighting implications for future policy and practice in this area.