The efficacy and side effects of buspirone compared with methylphenidate (MPH) in the treatment of children with attention-deficit/hyperactivity disorder (ADHD). A total of 34 children with ADHD as defined by DSM-IV-TR were randomized to buspirone or methylphenidate dosed on weight-adjusted basis at buspirone (0.5 mg/kg/day) and methylphenidate (0.3-1 mg/kg/day) for a 6-week double-blind clinical trial. The principle measures of outcome were the teacher and parent ADHD Rating Scale. The side effects were assessed by the special side effect checklist of each drug. In both groups, the scores of teacher and parent ADHD Rating Scale significantly declined on the 6th week as compared to baseline (p = 0.001). These effects were observed in the subscales too. No significant differences were observed between the two protocols on the total scores of parent and teacher ADHD Rating Scale, but methylphenidate was superior to buspirone in decreasing the symptoms of inattention. The side effects of buspirone were mild and rare in comparison with MPH. Buspirone has a favorable side-effects profile. It also has clinically and statistically significant impacts on improving the ADHD symptoms in children. These preliminary findings of the efficacy of buspirone in children with ADHD need large and cross-over studies.