OBJECTIVE: Prediction of a recurrent febrile seizure during subsequent episodes of fever. DESIGN: Study of the data of the temperatures, seizure recurrences, and baseline patient characteristics that were collected at a randomized placebo controlled trial of ibuprofen syrup to prevent febrile seizure recurrences. SETTING: Two pediatric hospitals in the Netherlands. PATIENTS: A total of 230 children with an increased risk of febrile seizure recurrence. MAIN OUTCOME MEASURE: Seizure recurrence during a subsequent fever episode. RESULTS: A total of 509 episodes of fever were registered with 67 recurrences; 35 (52%) recurrences within the first 2 hours after fever of onset had a lower median temperature (39.3 degrees C) than 32 (48%) after more than 2 hours of fever (40.0 degrees C, P<.001). Poisson regression analysis resulted in 3 univariably significant (P<.05) predictors of a recurrence of seiz