Accurate data are always needed to inform health policy, but are especially critical in tackling health inequities. The growing number of field research stations in sub-Saharan Africa are well-placed to generate relevant data and so support health policy action. Over the past 60 years, demographic surveillance systems have been crucial research tools for the evaluation of health interventions aimed at reducing socioeconomic differentials in mortality and morbidity in sub-Saharan Africa. The bulk of such work has been carried out by field research sites, often operating in remote, resource-constrained settings. The present paper reviews what we have learned since the pioneering work carried out in the field sites of Pholela (South Africa) and Niakhar (Senegal). It then focuses on current efforts to address health equity through INDEPTH, the international network of field sites with continuous demographic evaluation of population and their health in developing countries.