Poor people lack access to health care with a negative impact on their dignity, human capital formation and their risk-management options. Recently an emerging movement of community-based health insurance schemes has attracted the attention of policy makers and researchers as it seems that these schemes target the poor more efficiently. Taking the example of community-based health insurance schemes in rural Senegal this paper identifies the factors explaining participation in these schemes. Using household survey data of non-members and members, we found that household income, religion, village characteristics and the belonging to a certain ethnic group exert the strongest influence on the probability of participation. From these findings, it follows that i) although the schemes reach the "poor" in general, the "poorest of the poor" within the villages find it financially difficult to participate; ii) social exclusion due to religion or ethnic group might persist. Several options ...