The objective of this study is to investigate the efficacy of divalproex sodium in reduction of epileptiform EEG discharges in children with Autism Spectrum Disorders (ASD). ASDs are neurodevelopmental disorders that result in abnormalities of social and language development and are associated with rigid and repetitive behaviors. ASD prevalence may be as common as 1 in 110 and as many as 1/3 of these individuals have seizures. Abnormal electroencephalograms (EEGs) (without seizure activity) are even more prevalent (Spence & Schneider, 2009). In an ongoing study at the NIMH, approximately 50% of children without epilepsy had epileptiform discharges present on overnight EEG. The relationship between this abnormal activity and autism symptoms has not yet been studied; however, data from other epilepsy syndromes suggest that these epileptiform discharges contribute to behavioral and cognitive deficits. It is also unknown whether or not reduction of the epileptiform discharges will result in improved behavior and more rapid intellectual and social development in children with ASD. This pilot study is designed to address that question.