Objective: To evaluate the efficacy of a behavioral psychosocial treatment integrated across home and school (Child Life and Attention Skills Program) with attention-deficit/hyperactivity disorder (ADHD) predominantly inattentive type (ADHD-I). Method: Sixty-nine children ages 7 to 11 years were randomized to the Child Life and Attention Skills Program or a control group who did not receive the intervention. We compared groups posttreatment and at 3- to 5-month follow-up on parent and teacher ratings of inattention, sluggish cognitive tempo, and functional impairment. Results: Children randomized to the Child Life and Attention Skills Program were reported to have significantly fewer inattention and sluggish cognitive tempo symptoms, and significantly improved social and organizational skills, relative to the control group. Gains were maintained at follow-up. Conclusions: Behavioral psychosocial treatment, when specifically adapted for ADHD-I and coordinated among parents, teachers, and children, appears efficacious in reducing symptoms and impairment associated with ADHD-I. (Contains 2 tables and 1 figure.)