Six patients (3M, 3F, mean age 17.3 yrs) presenting different types of evolution from disorders of arousal to epilepsy are described. All subjects during their childhood had been diagnosed in a sleep center as affected by sleep-walking (three cases) and night terrors (the other three). Successively they developed nocturnal events different from those previously exhibited and consisting of clear epileptic seizures, generalized tonic-clonic in one case and complex partial in five cases. Nocturnal monitoring allowed recognition of clear interictal paroxysmal activity in three patients, while ictal events were recorded in the remaining three. Anticonvulsant treatment (carbamazepine in five patients, phenytoin in one patient) led to the resolution of the ictal events in all cases. The fact that both disorders of arousal and epilepsy are strictly related to sleep and often share common features such as age range of onset and precipitating factors, suggests the existence of common functional substrates identifiable in constitutional maturative and biologic factors. The possible occurrence of seizures in subjects exhibiting parasomnia during their childhood has to be considered in patients with familial history of epilepsy and in all doubtful cases.