Background Budesonide/formoterol (Symbicort ® ) as needed (PRN) is effective for the prevention of severe exacerbations in mild asthma. Objective This economic model evaluated the cost effectiveness of budesonide/formoterol PRN versus (1) a short-acting β 2 -agonist (SABA) PRN and (2) maintenance budesonide plus SABA PRN for mild asthma in Malaysia. Methods A decision analytical model was developed to evaluate the downstream economic consequences of the comparators from the payer's perspective (i.e. Ministry of Health, Malaysia) with a fixed time horizon of 1 year, and no discounting was applied. Data were derived from published clinical trials (i.e. SYGMA 1, SYGMA 2, and Novel START), the latest Malaysian resources, and an expert panel. The incremental cost-effectiveness ratio (ICER) per severe exacerbation avoided was determined. Sensitivity and scenario analyses were conducted to examine the robustness of the model. Results Treatment with budesonide/formoterol PRN (Malaysian ringgit [RM]773.39) had a lower total annual cost than SABA PRN (RM908.27) but a slightly higher cost than maintenance budesonide (RM760.51). The main cost driver was the disease management cost. Budesonide/formoterol PRN was a dominant intervention compared with SABA PRN and was associated with an ICER of RM696.11 per severe exacerbation avoided compared with maintenance budesonide. Scenario analysis with data from the Novel START trial indicated that budesonide/formoterol PRN was a dominant intervention compared with both SABA PRN and maintenance budesonide. Model outcomes were most affected by the mean inhalation of budesonide/formoterol PRN, the cost of managing severe exacerbations in hospital, and the probability of severe exacerbations with maintenance budesonide. Conclusion From the Malaysian healthcare payer perspective, budesonide/formoterol PRN is either a dominant or likely to be a cost-effective treatment option in managing mild asthma.