Nigeria is one of the few countries in the developing world that has systematically decentralized the delivery of basic services in health and education to locally elected governments and community-based organizations. Its health policy also has also been guided by the Bamako Initiative to encourage and sustain community participation in primary health care services. This study uses an extensive survey of primary health facilities and local governments to analyze how local institutions government and community-based function in practice in delivering basic health services, and to draw lessons for improving public accountability. The research was carried out in June-August 2002 in 30 local government areas of Lagos and Kogi states. Treasurers and primary health care coordinators in each of the 30 local governments, as well as managers and staff members in 252 health facilities were interviewed. Data from over 700 health workers was collected. In addition to its analytical objectives, the conduct of this study was specifically designed to promote evidence-based policy dialogue in Nigeria by engaging the active participation of the government agency responsible for monitoring and supervising outcomes in primary health care service delivery National Primary Health Care Development Agency (NPHCDA). The agency was closely involved at every stage of the survey from study design to its implementation and subsequent analysis.