10 children receiving stimulant medication for Attention Deficit Hyperactivity Disorder were compared to normal children on cognitive and neuropsychological dimensions in a pilot study. When compared with 10 normal children the ADHD children showed significant differences on cognitive measures, including the Wechsler Developmental Index, the Bender Visual-motor Gestalt Test, and the Benton Revised Visual Retention Test. Elevated levels of polyspike EEG activity were also noted for these children. Analysis suggested that ADHD children receiving stimulant medications may have persisting neuropsychological difficulty. Further research on the neuropsychological correlates of ADHD seems warranted.