We evaluated the clinical characteristics and the electroencephalographic (EEG) findings by long video-EEG monitoring in 64 successive patients with definite nocturnal seizures. Mental state, neurological examination, neuroimaging and EEG background were normal in all patients. Classification of epilepsies was possible in 42 out of 64 (66%) patients according to the revised Classification of Epilepsies and Epileptic Syndromes by the Commission on Classification and Terminology of International League Against Epilepsy (1989). Out of those 42 patients, 33 (79%) had partial epilepsies, while 9 (21%) had generalized epilepsies. Response to antiepileptic drugs was excellent and only 4 (6%) patients had one seizure attack per year, two of them were on two antiepileptic drugs while the others were free of seizure on a single drug during the 2 years of follow-up. It seems that nocturnal seizures in adults form a new distinctive partial epileptic syndrome of a benign entity.