Prognosis in Late-Onset Febrile SeizurePurpose: There is a paucity of evidence about prognosis after a first febrile seizure in older children. We investigated the prognosis and potential risk factors associated with subsequent unprovoked seizures in children who had experienced a first febrile seizure over 6 years of age, which we termed as late-onset febrile seizure. Methods: We included all patients six years or older who presented to the emergency department with a febrile seizure between 2009 and 2015. Clinical data was collected by chart review and parents were contacted for information on seizure progress. We used the Cox proportional-hazards model and Kaplan-Meier analysis for evaluating the risk factors for subsequent unprovoked seizures. Results: Of 247 patients, we excluded 168 children who had a history of epilepsy, unprovoked, or febrile seizure and who were followed-up for period less than six months. Overall, 79 patients were classified as having had a first late-onset febrile seizure. During follow-up of 34.9±25.7(mean±SD) months, unprovoked seizure recurred in 7 of 79 patients (9%). The cumulative probability of seizure recurrence was 4% at 6 months, 6% at 1 year and 9% at 2 years. Clinical variables predictive of subsequent unprovoked seizures were not proved. Conclusion: This is the first multicenter study focusing on prognosis after a lateonset febrile seizure in children six years or older. The percentage of subsequent unprovoked seizure in patients with late-onset febrile seizure was 9% at 2 years of follow-up. Prospective follow-up study with longer duration is warranted.