PURPOSE: Neonatal seizures are one of the most common neurologic manifestations in neonates and could be the important clinical sign of underlying brain disorders. The aim of this study is to review the clinical characteristics and to find the prognostic factors related to the outcomes of neonatal seizures. METHODS: We reviewed medical records retrospectively in 23 patients with neonatal seizures who admitted to Dankook University Hospital from July 2007 to June 2009. RESULTS: During the study period, neonatal seizures were diagnosed in 23/1,474 (1.56%) neonates. Nineteen of them (82.6%) were term and 4 were preterm. The main cause of neonatal seizures was hypoxic ischemic encephalopathy (n=8, 35%). Other various causes included metabolic disorders (n=4, 17%, carnitine palmitoyl transferase 1 deficiency, severe hypernatremic dehydration, prolonged severe hypoglycemia, and pyridoxine dependent seizure), intracranial hemorrhages (n=2, 9%), congenital brain anomaly (callosal dysgenesis, hemimegalencephaly) (n=2, 9%), and infection (congenital syphilis, early neonatal sepsis, n=2, 9%). Among nineteen neonates (82.6%) who were treated with anticonvulsants, we could not stop the anticonvulsants in six of them (32%). They had severe HIE, prolonged severe hypoglycemia with residual encephalomalatic changes, sinovenous thrombotic hemorrhages due to antithrombin III deficiency, congenital brain anomaly, and septic shock, respectively. CONCLUSION: Approximately one third of neonatal seizures were caused by HIE, and moderate to severe HIE had more serious outcomes. Neonatal seizure could be a significant clinical sign indicating specific underlying etiologies such as stroke, metabolic disturbances or congenital brain anomalies. Therefore, intensive workup and prompt management for neonatal seizures should be considered for better outcomes.