Nine highly verbal, nonretarded men, ages 18 to 39, with clearly documented childhood diagnoses of infantile autism were studied with the Wisconsin Card Sorting Test, a measure of conceptual problem solving sensitive to frontal system dysfunction, and with a measure of social-adaptive functioning. Their performances were compared with 10 controls matched for age, sex, education, and IQ, as well as with published norms for various groups of brain-damaged patients. Significant deficits in the formulation of rules and significant perseverative tendencies were documented in the autistic sample. No significant correlation between these deficits and social-adaptive deficits was seen. These findings were discussed with respect to the heterogeneity of the autistic disorder and Damasio's hypothesis concerning frontal-subcortical dysfunction in autism.