PURPOSE: Febrile seizure is a common neurological disorder in children and it has been reported that it may progress to epilepsy in a few cases. We have set forth to carry out a prospective study of patients who developed epilepsy after febrile seizures to determine their clinical characteristics. METHODS: The subjects of this research were 104 patients who met WHO's definition of epilepsy after at least 6 months had passed since their first seizure of the 612 patients admitted to the pediatrics department of Kyung-hee Medical Center during 5 years from January of 1993 to January of 1998 for their first febrile seizure. Epilepsy was categorized as epileptic seizure according to ILAE(1981). RESULTS: 1) The incidence of epilepsy was highest in children from 3 years to 5 years. 2) Of 104 children who developed epilepsy, 60 children were males and 44 were females. 3) Of children who eventually developed epilepsy, 37% of them had the family history of seizure. 4) Of 612 cases of first attack febile seizure, generalized tonic-clonic type was the most frequent type and at the time of diagnosis of epilepsy, generalized tonic-clonic type was also the most frequent type. 5) The abnormal EEG findings are found in 95% of children who developed epilepsy. CONCLUSIONS: We observed the clinical characteristics of patients who developed epilepsy after febrile seizures, but we feel that continuous research is necessary in establishing a correlation between the two disorders.