Since 2010, Nigerian state and federal governments and the international community have been responding to an outbreak of lead poisoning caused by the processing of lead-containing gold ore in Zamfara State, Nigeria, that resulted in the deaths of approximately 400 children aged ≤ 5 years. Widespread education, surveys of high-risk villages, testing of blood lead levels (BLLs), medical treatment, and environmental cleanup all have been implemented. To evaluate the success of these remediation efforts in reducing the prevalence of lead poisoning and dangerous work practices, a population-based assessment of children's BLLs and ore processing techniques was conducted during June-July 2012. The assessment found few children in need of medical treatment, significantly lower BLLs, and substantially less exposure of children to dangerous work practices. Public health strategies designed to identify and treat children with lead poisoning, clean up existing environmental hazards, and prevent children from being exposed to dangerous ore processing techniques can produce a sustained reduction in BLLs.