Forty-three neonates with status epilepticus of unidentified etiology were studied by EEG. 90% had favorable outcome. In the cases with unfavorable evolution the following criteria allowed an early poor prognosis: a very early onset of the seizures in the first or second day of life, the presence of tonic seizures and hypertony between seizures, duration of the seizures more than 4 days, EEG activity in the frequency of the alpha band during the seizures, a flat tracing after the seizures, very discontinuous activity between the seizures and, finally, the reappearance of seizures after a seizure-free interval. In the cases of favorable outcome, an EEG follow-up is necessary: in 10% of these cases focal spikes appeared after 2 years without seizures. The necessity of prolonged anti-comital treatment is discussed.