We discuss the presumptive etiologic factors of symptomatic epilepsy from the clinical standpoint, based on our experience of 383 inpatients with epilepsy, with a focus on children. The main (top three) presumptive etiologic factors in partial epilepsy are intracranial infection, cerebral malformation and perinatal brain damage. In generalized epilepsy, the main presumptive etiologic factors are perinatal brain damage, intracranial infection, and cerebral malformation. As regards presumptive etiologic factors in partial epilepsy, cerebral malformation was most common in frontal lobe epilepsy, initial convulsive status in temporal lobe epilepsy and perinatal brain damage in occipital lobe epilepsy. Electroclinical characteristics of severe myoclonic epilepsy in infancy, the most intractable epilepsy syndrome in infancy, is the focus and recent advances of genetic research are introduced.