The authors report on a series of 72 patients (57 male, 15 female; aged from 4 to 21 years) affected by autism with the aim of evaluate their experience regarding the prevalence of seizure and/or epilepsy. Patients were divided into two groups: the first includes individuals (n = 54) affected by so-called idiopathic or primary autism which was further subdivided according to the grade of mental retardation (MR) and the second (n = 18) in which a known pathological event was associated to the autism (secondary autism). According to these results in the first group 12 % of autistic patients with moderate MR (i.e., IQ > 55) suffered from seizures but in three patients (9 %) they were occasional and only in one recurrent (i.e., epileptic) (3 %). Autistic patients with severe MR (i.e., IQ < 55) suffered from seizures in 20 % of the cases: in three the episodes were recurrent (15 %) and in one occasional (5 %). In the second group in which autism was associated to other morbidities 61 % (n = 11/18) had seizures, being recurrent in 10 (55 %). According to this series, in autism the risk of epilepsy is higher compared to the general population but it does not seem to be correlated to the autism itself, but rather to the associated co-morbidities and underlying brain dysfunction (overall prevalence of epilepsy in primary autism [4/54 or 7.4 %] vs. secondary autism [10/18 or 55 %]).