The aims of this study were (1) to define the role of long-term computer-assisted outpatient electroencephalographic monitoring (COEEG) in children and adolescents with known or suspected epilepsy, and (2) to compare COEEG data with routine interictal electroencephalograms (EEG). We performed 18-channel COEEG in 84 children and adolescents with diagnosed (group 1, n = 49) or suspected (group 2, n = 35) epilepsy. Mean recording time was 1.4 days. Overall, COEEG was useful in 87% of patients. In group 1, events were recorded in 73% of patients and were electrographic seizures in 45%. In group 2, events were detected in 86% of patients and were electrographic seizures in 17%. Nocturnal and partial seizures predominated. Seizure diagnosis and classification by COEEG was concordant with interictal EEG findings in 19% and discordant in 63% of patients. COEEG is a useful technique for the diagnosis of epileptic and nonepileptic events among selected children and adolescents. When compared to routine interictal EEG, COEEG could offer additional accuracy in the classification of seizures in pediatric patients.