Autism is increasingly viewed as an expression of an unidentified neurological disorder. Because understanding of neurological dysfunction is basic to evaluation and treatment in occupational therapy, this article provides a comprehensive and critical review of the literature since 1985 concerning the neuropsychology of autistic disorder. The research is categorized into four basic types: (a) neuropsychological testing of functional abilities, (b) treatment studies based on neuropsychological hypotheses, (c) autistic-related diseases and genetic disorders, and (d) neuroanatomical and neurophysiological studies. The research shows a spectrum of neurological impairments within the brain stem, cerebellum, midbrain, and frontal lobe. These impairments are associated with deficits in socioemotional skills, sensory processing, motor planning, and cognitive flexibility. This research suggests that persons with autistic disorder need evaluation and treatment of a wide spectrum of functional deficits.