To determine the prevalence of major neurologic disorders, a door-to-door survey was conducted in six cities of the People's Republic of China during 1983 in a well-defined population of 63,195. The survey included a complete census and a screening interview together with an examination having high sensitivity for detecting individuals with frequently occurring neurologic disorders, including epilepsy. All individuals with responses or findings suggesting neurologic disease were examined by senior neurologists using standardized diagnostic criteria. There was 100% cooperation among the study subjects. Two hundred eighty-nine individuals alive on prevalence day (January 1, 1983) were identified as having epilepsy, yielding a lifetime age-adjusted (to the 1960 U.S. population) point prevalence ratio of 4.4/1,000. There were 16 people who developed epilepsy in the sample population during 1982, providing an age-adjusted incidence rate of 35/100,000 per year. The most frequent type identified was generalized convulsive seizures. Brain injury, intracranial infection, and cerebrovascular disease, in that order, were the leading putative causes of epilepsy.