Autism is a severe neurodevelopmental disorder that affects many individuals around the world, with a constantly increasing prevalence. The association between autism and electroencephalographic (EEG) abnormalities in children suggests a worse evolution of clinical features. A retrospective study was conducted, including 101 children with autism who underwent clinical and neurological examination and wake electroencephalography. This study aimed to examine EEG abnormalities in children with autism, identify phenotypic characteristics associated with these abnormalities, asses their clinical relevance, and determine potential phenotypic correlations. The results showed that 10.89% of the patients in the study presented EEG abnormalities, similar to those of other studies that used wake EEG. Of these patients, 18.18% presented epileptic-type discharges, such as spike and wave complexes, and 81.81% presented non-epileptic-type abnormalities, such as bursts of slow waves, generalized or focal. Regarding the phenotypic profile of the patients with EEG abnormalities, 45.45% had a positive family history, 63.63% presented with dysmorphic features and 27.27% presented with gait disturbance. This study shows that some children with autism present multiple EEG abnormalities and diverse phenotypic traits in terms of personal and family history, dysmorphic features, and neurological examination. Identifying EEG abnormalities can improve clinical decisions with complex treatment and monitoring of co-occurring conditions like epilepsy. The use of accessible, effective, and noninvasive assessment tools, such as EEG recordings and neurological examinations in children with autism, can provide valuable support for improved case management.