Objective: To compare the cost-effectiveness of once-daily methylphenidate (OROS-MPH), atomoxetine and combined MPH/behavioral therapy in the treatment of ADHD in children 6-18 years of age, from a societal perspective. Methods: A decision tree was used to model response rates, costs and utilities for the three treatment arms over a two-year period (base-case) using evidence from clinical and economic literature. Costs & utilities were extrapolated for a 16-year period beyond base-case period until the patient reached adulthood. Both costs and utilities were discounted at the rate of 3%. A one-way sensitivity analysis of the ICERs was conducted to test assumptions made while modeling and to determine drivers of cost. Results: The base-case costs and QALYs for OROS-MPH, atomoxetine and combined therapy were US$ 8314, 9716, 10,723 and, 1.71, 1.73, 1.50 respectively. The extrapolated 12-year costs and QALYs were US$ 21,804, 25,435, 28,759 and, 6.28, 6.21, 6.08 respectively. The base-case CE ratios for stimulant, non-stimulant and combined therapy against no-treatment are US$ 8690.2, 12577 and 57,971.9 respectively. The base-case cost-effectiveness ratio of atomoxetine versus OROS-MPH is $60,782, while that of combined therapy against each of the other two interventions was negative. Sensitivity analysis showed that maintenance rates and utilities were the main drivers of cost-effectiveness. Conclusion: All three interventions are cost-effective as compared to no treatment option. Combined therapy was ‘dominated' both during the base-case as well as over long term periods. While atomoxetine is more cost-effective than OROS-MPH over a two-year period, the latter is the ‘dominant' strategy over the long term.