Most neonatal seizures are occasional seizures and not true epilepsy. This study investigates seizure types of true neonatal epilepsies and their evolution with development. Seventy-five children with epilepsies of onset within 1 month of life, who were examined between 1970 and 1995, and whose seizure types could be confirmed with ictal EEG recordings, were studied. The patients were followed up for a minimum of 3 years and the evolution of epileptic syndromes was investigated. Sixty-three (84%) of 75 patients had partial seizures, while nine had generalized seizures, and only three had both generalized and partial seizures. Twenty-three of 24 neonates with benign familial or non-familial neonatal convulsions presented with partial seizures; these syndromes should not necessarily be categorized into generalized epilepsy as they are in the present International Classification. Age-dependent changes were a common feature of symptomatic neonatal epilepsies. Eighteen (41%) of 44 patients with symptomatic epilepsies of neonatal onset developed West syndrome in infancy. Fifteen (83%) of these 18 patients presented with symptomatic localization-related epilepsy in the neonatal period. In seven of these 15 patients, West syndrome was followed by localization-related epilepsy. Symptomatic localization-related epilepsy with transient West syndrome in infancy is another type of age-dependent epileptic syndrome.