Research strategies which emphasize participation are increasingly used in health research. Breaking the linear mould of conventional research, participatory research focuses on a process of sequential reflection and action, carried out with and by local people rather than on them. Local knowledge and perspectives are not only acknowledged but form the basis for research and planning. Many of the methods used in participatory research are drawn from mainstream disciplines and conventional research itself involves varying degrees of participation. The key difference between participatory and conventional methodologies lies in the location of power in the research process. We review some of the participatory methodologies which are currently being popularized in health research, focusing on the issue of control over the research process. Participatory research raises personal, professional and political challenges which go beyond the bounds of the production of information. Problematizing "participation', we explore the challenges and dilemmas of participatory practice.