Although the current diagnostic criteria for childhood absence epilepsy (CAE) do not specifically exclude children with generalized tonic clonic seizures (GTCSs) occurring before or early in the course of the active absence seizures, some workers have suggested that they should be interpreted as doing so. The aim of this study was to compare the clinical features between children with typical CAE and those with atypical CAE with preceding or simultaneous episodes of GTCS (atypical CAE-GTCS).A total of 11 patients with atypical CAE-GTCS and 30 with typical CAE were identified by using the current CAE criteria. Their clinical data, including age, sex, family history of epilepsy, personal history of febrile convulsions, onset ages of absences and GTCS, treatment, and outcome were statistically analyzed.The two groups had the same mean onset age of absences (6years), and their seizure outcome was comparably favorable in terms of both absences and GTCS. There was no significant difference in other clinical data except for the onset age of GTCS between the groups.These findings show the similarity in the main clinical features between the groups, suggesting that some patients with atypical CAE-GTCS may have a variant form of CAE with early onset of GTCS.