Epileptic seizures are more common in the newborn period than at any other time of life. If ictal behaviors accompany ictal EEG discharges, there is no particular problem. However, the most pressing controversy is whether neonatal seizures should be diagnosed on the basis of behavioral or EEG criteria. The proportion of seizures that are subclinical is much higher during the neonatal period than at any other time of life. Therefore the frequent occurrence in an intensive care unit of both subclinical seizures and suspicious stereotyped behaviors renders EEG of critical importance in the diagnosis of neonatal seizures. The authors discuss the large field of clinical and EEG phenomenology of neonatal seizures after twenty years of experience with EEG in neonatology.