Objective: To assess the effect of atomoxetine on ADHD-related executive functions over a 6-month period using the Brown Attention-Deficit Disorder Scale (BADDS) for Adults, a normed, 40-item, self-report scale in a randomized, double-blind, placebo-controlled clinical trial. Method: In a randomized, double-blind clinical trial, adults with ADHD received either atomoxetine 25 to 100 mg/day or placebo for 6 months. Patients completed the BADDS to report their current daily functioning in 5 clusters of ADHD-related impairments of executive functioning: (1) Organizing and Activating to Work; (2) Focusing for Tasks; (3) Regulating Alertness and Effort; (4) Modulating Emotions; and (5) Utilizing Working Memory. Results: Mean scores were significantly more improved in the atomoxetine group compared to the placebo group: total score, -27.0 versus -19.0 (p less than 0.001); all 5 cluster scores, p less than 0.01. Conclusions: Once-daily atomoxetine can improve executive function impairments in adults with ADHD as assessed by the BADDS. (Contains 2 tables and 2 figures.)