BackgroundWe determined the prevalence, incidence, and risk factors for epilepsy in Nigeria.MethodsWe conducted a door-to-door survey to identify cases of epilepsy in 3 regions. We estimated age-standardized prevalence adjusted for nonresponse and sensitivity and the 1-year retrospective incidence for active epilepsy. To assess potential risk factors, we conducted a case-control study by collecting sociodemographic and risk factor data. We estimated odds ratios using logistic regression analysis and corresponding population attributable fractions (PAFs).ResultsWe screened 42,427 persons (age ≥6 years), of whom 254 had confirmed active epilepsy. The pooled prevalence of active epilepsy per 1,000 was 9.8 (95% confidence interval [CI] 8.6–11.1), 17.7 (14.2–20.6) in Gwandu, 4.8 (3.4–6.6) in Afikpo, and 3.3 (2.0–5.1) in Ijebu-Jesa. The pooled incidence per 100,000 was 101.3 (95% CI 57.9–167.6), 201.2 (105.0–358.9) in Gwandu, 27.6 (3.3–128.0) in Afikpo, and 23.9 (3.2–157.0) in Ijebu-Jesa. Children's significant risk factors included febrile seizures, meningitis, poor perinatal care, open defecation, measles, and family history in first-degree relatives. In adults, head injury, poor perinatal care, febrile seizures, family history in second-degree relatives, and consanguinity were significant. Gwandu had more significant risk factors. The PAF for the important factors in children was 74.0% (71.0%–76.0%) and in adults was 79.0% (75.0%–81.0%).ConclusionThis work suggests varied epidemiologic numbers, which may be explained by differences in risk factors and population structure in the different regions. These variations should differentially determine and drive prevention and health care responses.