After reviewing the health status of disadvantaged population groups (the underprivileged, migrants) and the reasons for this situation (difficulty accessing care, and even exclusion, living conditions), the author outlines the health and social measures taken both at the national level (R.M.I., the law granting access to social security benefits, and the expansion of health promotion) and at the local level (description of a number of municipal initiatives, such as the introduction of the health card in Besançon), as well as the work of humanitarian organizations, such as the ATD-Quart Monde movement.