The objective of the present study was to make a clinical and electroencephalographic characterization of the electrical findings and types of seizures in patients with idiopathic autism. Pediatric patients of any age, with the diagnosis of idiopathic ASD, contained within the database of the research “Genetic in autism” were included. An electroencephalographic recording with epilepsy protocol was performed in all the patients. 20 pediatric patients were included with an age media of 10.5 years, SD 5.48 years. The median age for the diagnosis of ASD was 53 months, and epileptic seizures were documented in 45%. 66.6% of patients with epileptic events had anti-epileptic treatment, and only 33.3% had achieved seizure control with medication. Interictal abnormal EEG records were found in 8 patients (40%), with 6 of them having epileptic seizures. The abnormal EEG activity was multifocal in 62.5%, focal in 25% and generalized in 12.5% of the cases. The most frequently compromised location was the temporal lobe.