OBJECTIVES: To investigate the cost-effectiveness of using an increased dose of disodium cromoglycate versus switching to budesonide treatment in those asthmatic children whose symptoms can not be controlled with the recommended dose of cromoglycate. METHODS: An open, randomized, parallel group design clinical trial was conducted at 20 study centres. After a 4-week run-in period, 131 children with uncontrolled symptoms were randomized either to the treatment of increased disodium cromoglycate 4x40mg daily or budesonide 2x200?g daily for a 12-week treatment period. An intention-to-treat analysis was performed. Efficacy variables were the morning PEF value, PEF variability, FEV1, and the number of symptom free days. The economic analysis was based on a societal perspective. Protocol driven costs were excluded. Direct costs were measured as costs of treatment drugs, rescue medication, non-protocol driven visits, and number of days in hospital. Indirect cost measurement was based on time missing from school. A sensitivity analysis was carried out on the use of rescue medication to test final cost-effectiveness. RESULTS: As sample size was powered to detect differences in PEF values only, differences in FEV1 values, hospital stay, days missed from school and physician visits did not reach statistical significance. The morning PEF value increased more from baseline in the budesonide group (35.01 vs. 13.64; p=0.02). PEF variability decreased more in the budesonide group (10.1 vs. 5.4; p=0.055). The average number of symptom free days was higher in the budesonide group (65.7 vs. 59.5; p=0.09). The average number of occasions using rescue medication was 14.58 (8.36; 20.81, p=0.05) versus 27.48 (12.82; 42.15, p=0.05) in the budesonide and cromoglycate group respectively. The cost per symptom free day was HUF 51 in the budesonide group and HUF 272 in the cromoglycate group. CONCLUSIONS: Budesonide treatment was the dominant strategy as it lead to both superior clinical outcomes and cost savings.