PURPOSE: The greatest concern for children with febrile seizures is not only the possibility of epilepsy, but also unprovoked seizures. The present study examined the risk and predictors of unprovoked seizures. Study factors include three identified factors of unclear significance-family history of febrile seizures and the number of recurrent febrile seizures and two new factors that are important predictors - the height of temperature and the duration of fever prior to the initial febrile seizure. METHODS: Children(n=333) between 6 months and 5 years of age with first febrile seizures were reviewed to determine the risk and predictors of unprovoked seizures for 10 years. Children with the central nervous system infections(meningitis or encephalitis), past history of febrile seizures or epilepsies were excluded. RESULTS: 10(43.5%) of 23 children with neurodevelopmental abnormalities had epilepsies. 12(10%) of 120 children with complex febrile seizures had epilepsies. 17(6.6%) of 256 children without family history of febrile seizures in 1 degrees relative and 8(10.4%) of 77 children with family history of febrile seizures in 1 degrees relative had epilepsies. CONCLUSION: In our results, there exists a strong association between unprovoked seizures and complex features in neurodevelopmentally abnormal children compared with normal children.