Many children with autism spectrum disorders (ASD) have unusual responses to sensory stimuli. They may be overly sensitive to sensation and thus respond to stimuli too easily or too intensely. These responses to stimuli and the associated difficulties in processing sensory information (together referred to as sensory dysfunction) are significant factors limiting the child and family's ability to participate in activities in the home and the community. Interventions such as occupational therapy have been used to specifically address these sensory dysfunctions, but their efficacy has not been evaluated in controlled studies. The present study will evaluate whether a systematic intervention of occupational therapy is effective in decreasing sensory dysfunction in children with ASD. Subjects will work with occupational therapists with expertise in evaluating and treating sensory dysfunction, who will focus on enhancing independence and participation in activities. After occupational therapy, the subjects' ability to participate in home, school and community activities will be assessed, and improvements in their sensory behaviors will be measured. This study will provide parents and therapists with much needed data about the usefulness of occupational therapy to address sensory dysfunction in ASD, and has the potential to provide effective strategies to enhance participation in everyday activities.