OBJECTIVE: To estimate the cost-effectiveness of atomoxetine for the treatment of children and adolescents with Attention Deficit/Hyperactivity Disorder (ADHD) in Norway. METHODS: A modelled economic evaluation calculated the incremental cost per quality-adjusted life years (QALYs) gained of atomoxetine compared to two stimulant therapies and “no medication”. Treatment algorithms with and without atomoxetine were compared in patient subgroups stratified by prior treatment history and whether stimulant medication was appropriate. A Markov process incorporated fourteen health states representing hypothetical treatment outcomes for which utility values were sought from parents of patients through survey. Aspects of effectiveness and safety of each medication were based on a review of controlled clinical trials and other clinical literature. Monte-Carlo simulation was run over a one-year duration from the perspective of the Norwegian healthcare system. RESULTS: In stimulant-naive patients, the incremental cost per QALY of atomoxetine was NOK 199,178 and NOK 149,892 when compared to immediate-release (IR) and extended-release (XR) methylphenidate, respectively. In stimulant-failed patients, the incremental cost-effectiveness of atomoxetine was NOK 168,154 per QALY gained. The incremental cost per QALY of atomoxetine compared to no medication in patients contra-indicated for stimulants was NOK 175,105. Sensitivity analysis showed that the utility values for each treatment were important determinants of the cost-effectiveness of atomoxetine. CONCLUSIONS: Results of the modelled economic evaluation suggest atomoxetine offers a value-for-money alternative in the treatment of children with ADHD in Norway.