Children with complex febrile seizures (CFS) have increased risk for the development of epilepsy, but varying prognostic value has been ascribed to abnormal post-CFS electroencephalograms (EEGs). We conducted a retrospective cohort study of 621 children with post-CFS EEGs and identified an association between CFS and midline-vertex discharges, which were present in 52% of the 56 EEGs with interictal epileptiform discharges. Among patients who completed at least 1 year of follow-up, 24.7% subsequently developed epilepsy. Most patients had normal EEGs but 20% had interictal epileptiform discharges. Midline-vertex discharges were seen at a similar rate in children who did not develop epilepsy (55%) and those who developed epilepsy (45%). The development of epilepsy was not associated with any interictal epileptiform discharge localization. Logistic regression modeling identified 4 predictors of future epilepsy: >3 febrile seizures in 24 hours, interictal epileptiform discharges during post-CFS EEG, family history of afebrile seizures, and age of CFS onset ≥ 3 years.