Autism Spectrum Disorders (ASDs) are associated with disturbed sleep and p articularly with difficulties initiating and maintaining sleep (i.e., insomnia). The severity of these sleep disturbances correlates with increased emotional and attentional problems and more aggressive behavior. This study focuses on brain regions underlying altered social behavior in autism that are normally responsible for the ability to understand the mental states of others. Given the now overwhelming evidence that sleep plays a critical role in learning and memory, and particularly procedural learning, investigations of the role of abnormal sleep in the cognitive, emotional, social and behavioral deficits of ASD are of great importance. The primary goal of this study is to investigate the hypothesis that impaired sleep-dependent emotional and memory processing due to poor sleep plays a key role in the cognitive and behavioral deficits seen in children with ASD and make it difficult for them to benefit from remedial interventions. Specifically, the study will determine whether poor sleep in children with ASD, measured polysomnographically in the laboratory, correlates with impaired sleep-dependent consolidation of probabilistic category learning, as well as with poorer performance on a range of cross-sectional measures of cognitive function, emotional stability, repetitive behaviors and social skills. This will be the first study of sleep-dependent consolidation of learning and memory in ASD. This work will be important in understanding the phenotype of ASD and is a critical first step to designing interventions to improve sleep and daily functioning in individuals with ASD.