The aim of this work is to identify the effect of age on cost-effectiveness in the treatment of moderate asthma patients with inhaled corticosteroids. METHODS: The cost-effectiveness analysis was conducted as a retrospective analysis of clinical trial data. The data of one open and one double-blind multicentre, parallel group study comparing the efficacy of Fluticasone and Flunisolide was pooled. The pooled intent-to-treat (ITT) group consisted of 308 patients. Because of the retrospective nature of the study, only the cost of treatment medication and of concomitant medication were included. No hospital admission occured. The costs caused by adverse events were identified to be negligable and therefore omitted. Since physicians’ visits were protocol driven they were also excluded. Effectiveness (successfully treated patients) was defined by an increase in peakflow of 5% or more. Total treatment costs for each age group were calculated and devided over the number of patients fullfilling the effectiveness criterion. RESULTS: Total average daily treatment costs per patient were DM 4.58 (SD: DM 1.61). The average cost-effectiveness ratio per successfully treated patient was DM 7.84 (SD = DM 1.72). The cost-effectiveness ratios were positively correlated to age (p<0.05). This effect was caused by slightly rising total treatment costs over age and a declining number of patients fullfilling the effectivness criterion. CONCLUSION: Cost-effectiveness ratios are positively correlated to age in the treatment of moderate asthmatics.