Many studies have shown a significant relationship between religion and health in Western countries. In developing countries, however, there is a dearth of scientific studies on the matter. Using data from the Ouagadougou Health and Demographic Surveillance System, this paper examines religious differences in child vaccination rates in five districts of Ouagadougou, Burkina Faso. It tests the applicability of the selectivity hypothesis, which holds that religious differences in health come from underlying differences in the socioeconomic and demographic composition of religious communities. In our study population, even when socioeconomic and demographic characteristics are taken into account, an effect of religion on child vaccination rates was observed. This suggests that religious disparities in child vaccination rates are not solely due to the makeup of different religious communities, but also to ideological differences and/or to diffusion effects from interactions within religious groups. The religious differences demonstrated here suggest that a greater emphasis should be put on community-based approaches involving religious leaders when addressing health disparities.