Primary health care (PHC) is again high on the international agenda. It was the theme of The World Health Report in 2008, thirty years after the Alma-Ata Declaration, and has been the topic of a series of significant conferences around the world throughout 2008. What have we learnt about its impact in improving population health and health equity? What more do we still need to know? These two questions frame a four-year international research/capacity-building project, 'Revitalizing Health for All' (RHFA), funded by the Canadian Global Health Research Initiative (http://www.idrc.ca/en/ev-108118-201-1-DO_TOPIC.html). The RHFA project is organised under the umbrella of the People?s Health Movement (http://www.phmovement.org/en) and the International People?s Health University (http://phmovement.org/iphu/), and involves researchers from over a dozen countries. Our project team?s understanding of PHC is of a comprehensive approach aimed at reducing health inequities that is based on meaningful community participation, multidisciplinary teams and action across sectors.