Objective: Although a number of epidemiologic studies have been conducted on the prevalence and incidence of epilepsy around the world, only a few studies have investigated the clinical characteristics of patients with epilepsy in a population-based sample. The purpose of the present study was to describe the clinical characteristics of treated patients with epilepsy in Korea via a nationwide medical records survey. Methods: The study population was obtained through a nationwide database registered to the Health Insurance Review and Assessment service. Patients were recruited from clinics and hospitals in each cluster according to region and referral level by random selection from a preallocated sample of patients. All patients were being treated with antiepileptic drug medication with or without a diagnosis code for epilepsy or seizure between January 2009 and December 2009. Among the 6,436 selected patients, 2,150 met the diagnostic criteria for epilepsy and were included in our survey on the clinical characteristics of patients who were with treated epilepsy. Results: The proportion of male patients with epilepsy in this study was higher (1,226; 57.0%) than that of female patients. In addition, 10.6% of patients were first diagnosed with epilepsy in 2009, and 53.6% of patients experienced at least one seizure over the course of 2009; 78.1% were classified as having localization-related epilepsy, whereas 7.3% were considered to have generalized epilepsy. Thirty-five percent of patients were thus classified as idiopathic or cryptogenic cases. The most common cause of symptomatic epilepsy was trauma (10.0%), followed by stroke (9.6%), central nervous system (CNS) infection (5.7%), and hippocampal sclerosis (4.9%).