Objective: Neuropsychological assessments conducted with children with Attention Deficit Hyperactivity Disorder (ADHD) often include both measures of broad behavioral ratings and levels of ADHD symptomatology. However, it is unclear the extent to which these two measures share substantial common variance or measure unique domains. In efforts to increase efficiency, clinicians may eliminate a measure from their assessment battery. Therefore, the current study examined this matter. Method Participants included 253 children with ADHD-Inattentive (n = 163) and ADHD-Combined (n = 90). Children were 10.4 years old and 70.4% male with a Full Scale IQ of 98.7. Diagnoses were established in a private practice through comprehensive evaluations, including administration of the Behavior Assessment System for Children, Second Edition (BASC-2) and DSM–IV ADHD Symptom Rating Scale (DSM–ADHD–SRS). Results There were significant moderate correlations between the respective mothers' ratings of Attention Problems/Inattention and Hyperactivity on the BASC-2 and DSM-ADHD-SRS parent ratings, p < .01. Additionally, there were low correlations between inattention and hyperactivity on these two measures. Item level analysis indicated that DSM symptoms of poor sustained attention, distractibility, and difficulty following directions were particularly related to BASC-2 ratings of Attention Problems. Conclusion These data suggest that it is valuable to examine both BASC-2 and DSM ratings of inattention and hyperactivity in clinical evaluations. While these ratings share common variance, each measure provides unique information in establishing current levels of functioning. Findings with these measures are also consistent with prior research indicating that inattention and hyperactivity are related but unique symptom domains.