Background: Epilepsy is strongly associated with Autism Spectrum Disorders (ASD). This high rate of epilepsy suggests that ASD and epilepsy might share a common pathophysiological basis. Objective: To study the characteristics of EEG findings and epilepsy in autistic spectrum disorders (ASD) and the associated neuropsychological symptoms. Methods: Sixty children with ASD, aged from 3 to 11 years old, were included in the study. EEG recordings were obtained for each child. All patients were evaluated with respect to clinical and familial characteristics and with the Childhood Autism Rating Scale (CARS). Results: The frequency of epileptiform EEG abnormalities in children with ASD was 40%, and the frequency of epilepsy was 30%. EEG abnormalities were associated with a diagnosis of epilepsy in 13.3%. Seizures and EEG changes were frequent among children with severe autism. Aggressive behaviours, hyperactivity and delayed developmental history were more frequent among patients with seizures. Sleep disturbance and hyperactivity were more common among participants with sever autism. On the other hand, aggressive behaviour and developmental delay were more common among patients with mild to moderate autism. Conclusion: Autism is one of the risk factors for epilepsy. Epilepsy occurs in one-third of patients with ASD. EEG abnormalities occur in 40% of patients with ASD. Epilepsy may be considered as one of the aggravating factors for behavioural/emotional outcomes for individuals with autism. Treatment of EEG changes might have a positive effect on the symptomatic improvement of children with ASD and EEGs changes.