The incidence and outcome of epilepsy in tuberous sclerosis (TS) patients have not yet been thoroughly investigated. The aim of this study was to evaluate the clinical features and prognosis of epileptic seizures associated with TS. The medical records of 29 patients who satisfied the diagnostic criteria for TS and were followed up for at least 2 years at the Department of Pediatrics, Chonnam National University Hospital (CNUH), between January 2000 and December 2010 were reviewed. Onset age of seizure, initial electroencephalography (EEG) findings, and efficacy of treatment were evaluated. Brain imaging studies were reanalyzed to determine the number of cortical tubers and subependymal nodules present. A total of 26 (89.6%) cases presented with seizures. In the seizure-controlled group (n=9, 34.6%), the mean number of cortical tubers was 4.5 (range, 0-16) and the mean number of subependymal nodules was 6.2 (range, 0-14). Initial EEG identified epileptiform discharges in 4 (44.5%) of these cases. In the seizure-sustained group (n=17, 58.6%), 10 patients had initial seizures before 1 year of age. In this group, the mean number of cortical tubers was 6.0 (range, 0-20) and the mean number of subependymal nodules was 6.0 (range, 1-11). A total of 15 (88.2%) had epileptiform discharges on their initial EEGs. In three patients who did not show any seizures during the observation period, the mean number of cortical tubers was 1.3 (range, 0-2), and the mean number of subependymal nodules was 4.6 (range, 0-13). Medical intractability of epilepsy in conjunction with TS did not correlate with age at onset of seizure, the number of cortical tubers, or subependymal nodules, but was associated with initial EEG findings.