What can other developing countries learn from Sri Lanka on achieving good health at low cost? While its well-organized medical and maternal-child health services have been documented elsewhere, this paper fills a gap in documenting how it organizes services to reduce the population's exposure to disease -- a pure public good. The key factors underlying the effectiveness of these services are (1) strong focal points in the central Health Ministry for supporting preventive services; (2) pro-active outreach by the health line agency to collaborate with other sectors / agents whose work influences public health outcomes; and (3) community-level delivery institutions with well-trained multivalent Public Health Inspectors -- all underpinned by (4) assured tax-based financing. This paper describes this system in some detail such that other countries can learn from Sri Lanka's successful approach to improving population health. It also makes some recommendations for strengthening the system in response to changing conditions