OBJECTIVE: To assess the comparability of atomoxetine, a new therapy for attention-deficit/hyperactivity disorder (ADHD) and methylphenidate. (Atomoxetine was originally called tomoxetine. The name was recently changed in order to avoid any potential confusion with tamoxifen that might lead to errors in dispensing drug.) METHOD: Children with ADHD were randomized to open-label atomoxetine or methylphenidate for 10 weeks. Response was assessed with the ADHD-IV Rating Scale. RESULTS: Two hundred twenty-eight patients were randomized (atomoxetine n = 184, methylphenidate n = 44). Both drugs were associated with marked improvement in inattentive and hyperactive-impulsive symptom clusters as assessed by parents and investigators. No statistically significant differences between treatment groups were observed on the primary outcome measure (investigator-rated ADHD-IV Rating Scale total score: atomoxetine baseline: 39.4 [8.5], endpoint: 20.0 [13.9]; methylphenidate baseline: 37.6 [9.7], endpoint: 19.8 (16.6); p = .66). Safety and tolerability were also similar between the 2 drugs. Discontinuations due to adverse events were 10/184 (5.4%) for atomoxetine and 5/44 (11.4%) for methylphenidate; p = .175. CONCLUSION: These data provide preliminary evidence that atomoxetine is associated with therapeutic effects comparable to those of methylphenidate.