PURPOSE:The aim of this study was to characterize the clinical and electroencephalographic features as well as the neurologic outcomes of GEFS+(Genenralized Epilepsy with Febrile Seizures Plus). METHODS:We evaluated 55 children with GEFS+ who admitted at the Department of Peditrics, Kangnam Sacred Heart Hospital from 1993 to 2004. We formed them into two groups by age of first febrile seizure; Group A(<6 years) and Group B(> or = 6 years). We analyzed the clinical features, electroencephalographic findings and the neurological outcomes of the subjects. RESULTS:The mean age of the initial febrile seizures of 55 subjects was 3 years and 9 months. 41 subjects had their initial febrile seizures under 6 years of age while 14 subjects after 6 years of age. 17 subjects had family history of seizures. The mean frequency of seizure is 4.4 times and the types of convulsions were mainly generalized. Nineteen(37.3%) showed abnormal finding on EEG and twenty three(41%) were treated with antiepileptic drug(AED) for long-term prophylaxis. Never the less, there was no subject with abnormalities in the neurological outcomes. The group with the initial seizures occurred under 6 years of age had more family history of seizures, higher frequency of total seizures, febrile seizures, and was administered with AEDs longer than the other group. CONCLUSION:In our study of GEFS+, the clinical features and the results of the electroencephalograms were various. While there were cases with a need of long term administration of AEDs, few cases of neurological abnormalities or developmental delay were seen. The group of the initial febrile seizures under 6 years of age revealed more family history of seizures, higher frequency of seizures than the other group.