24-hour EEG monitoring was performed in 403 children with repeated seizure of various types. The positive rate was 82.7% for defined epilepsy. Epileptic discharges mainly occurred in NREM stage and focal discharges accounted for 69%. More than 70% of the children suspected of epilepsy were excluded from epileptic seizures. 24-hour EEG monitoring is of significant value in determining seizure characteristics, epilepsy types, the relations between epilepsy and sleep and between clinical seizures and EEGs.