An epidemiologic study of adult patients (aged greater than 15 years) with epilepsy was made over a 2-year period, through the policlinics, EEG laboratory, and university hospitals in Benghazi, northeastern Libya. Based on a total of 568 patients (310 male and 258 female), the prevalence rate on 31 December 1984 was 2.3/1,000 in the population above the age of 15 years (1.9, if age standardized). The age-specific prevalence per 1,000 population decreased from 3.6 in the 15-24 year age group to 1 in the greater than 60-year age group. For 70.8% of the patients the onset of epilepsy occurred in the first 2 decades of life, and for 7.6% it commenced after the age of 40. The duration of epilepsy when first seen in the study period was less than 1 year in 14.6%, and greater than 10 years in 25.7%. The percentages of primary generalized, partial seizures secondarily generalized, simple partial, and partial complex seizures were 55.6, 18.8, 10.4, and 14.6%, respectively. Antecedents that could be considered potential causes of epilepsy were found in 17.5% of cases. Fifty-five patients had status epilepticus, 24 of whom had symptomatic epilepsy and eight recurrent status. EEG revealed generalized epileptic activity in 199 cases and focal seizure activity in 118. Computerized tomography (CT) scan, done in 219 patients, disclosed abnormal results in 50. Among those with abnormal CT scans, 84% had partial seizures. Monotherapy with carbamazepine or phenytoin was used in the majority of cases. The influence of social, cultural, and religious factors in the diagnosis and management of epilepsy as seen in Benghazi are discussed.