This report reviews what is currently known concerning the distribution and determinants of epilepsy in pediatric populations. Data on the magnitude of specific types of seizure disorders are presented, together with current information about the etiology, prognosis, and genetic aspects. Our understanding of the causes of epilepsy in children is still at a rudimentary stage, but results of epidemiologic investigations will provide a firm basis for the formulation and testing of hypotheses relating to etiology and prevention.