Ten men (ages 18-39) with clear histories of Infantile autism and approximately average verbal and nonverbal intelligence were studied with a comprehensive battery of neuropsychological tests. Comparisons with 10 matched normal controls showed no significant differences in many visuoperceptual or memory skills or in sensory-perceptual or motor skills or their lateralization. Differences seen on language measures were small, but statistically significant. In contrast to this, the autistic group demonstrated dramatic deficits on simple and complex, verbal and nonverbal problem-solving tasks, such as the Wisconsin Card Sorting Test, selected tasks from the Stanford-Binet, and the Trail Making Test. A left-hemisphere hypothesis of autism was not supported, nor was there compelling evidence of any posterior cortical deficit. Results are compatible with frontal-system dysfunction or with more widespread pathology.