Background There is growing evidence that people with dementia want to participate in research and benefit from their involvement. However, little attention has been given to date to the potential to involve people with dementia as co-researchers, not just participants. Aims The paper discusses the implications for people with dementia of involvement in research as co-researchers. Method Older people with dementia participated in planning the research methods, conducting interviews and making sense of the findings. Results The project found that it is possible to involve older people with dementia in a meaningful way in research processes and that both co-researchers and participants can benefit significantly from their participation. Conclusions The project has wider implications for the development of participatory research with people with dementia and for interventions based on peer support.