The purpose of this study was to determine if attention-deficit/hyperactivity disorder (ADHD) subtypes (predominantly hyperactive/impulsive, ADHD-HI; predominantly inattentive, ADHD-IA; combined, ADHD-C) exhibit distinct neuropsychological profiles, using the Attention and Executive Function subtests of the Developmental Neuropsychological Assessment, (NEPSY) and the omission and commission scores obtained on the Conners' Continuous Performance Test-II (CPT-II), a test that assesses attention processes. The sample was selected using archival data collected in a neurodevelopmental clinic over the past decade and consisted of 138 children between the ages of 6 and 12 years old. Using the Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV) criteria, the children were placed in either the ADHD-HI (n = 40), ADHD-IA (n = 35), or ADHD-C (n = 36) group, or a symptom free comparison group (n = 27). It was hypothesized that children with elevations on the impulsivity/ hyperactivity (ADHD-HI and ADHD-C) scale would be impaired on measures of inhibition and those with elevations on the inattention scale (ADHD-IA and ADHD-C) would be impaired on tests of attention, vigilance, and other executive functions. A one-way multivariate analyses of variance (MANOVA) was conducted (Group X Task), with significant results for overall main effect for group on the 7 …