Given the increasing number of therapies, purchasers and payers of healthcare are becoming more sensitive to the overall cost of treatment in relation to the clinical outcomes achieved. OBJECTIVE: The purpose of this economic analysis was to compare the value of an inhaled corticosteroid (ICS), fluticasone propionate 88mcg twice daily, versus a leukotriene receptor antagonist (LTRA), zafirlukast 20mg twice daily, in subjects with persistent asthma currently receiving short acting beta2-agonists alone. METHODS: The data utilized in the analyses was collected from a multi-center, randomized, double-blind, double-dummy, parallel group, placebo-controlled clinical trial. Effectiveness parameters included in this economic analysis were the proportion of symptom-free days (SFD), and QOL improvements (>0.5 change from baseline). Direct costs (D) included: costs of study drugs, emergency room visits, hospitalizations, unscheduled physician visits, treatment costs for drug-related adverse events, and rescue medication (albuterol). Indirect costs (I) included: lost wages and benefits associated with missed workdays or school days. All costs are reported in 1998 dollars. RESULTS: 329 patients were randomized to receive ICS (n=111), LTRA (n=107), or PL (n=111). The cost effectiveness (CE) ratios in terms of SFD, were $6.62 (D); $8.86 (D+I) for ICS compared to $12.08 (D); $14.15 (D+I) for LTRA. The CE ratios for QOL, were $1.90 (D); $2.54 (D+I) for ICS compared to $2.61 (D); $3.06 (D+I) for LTRA. The cost-effectiveness ratios were in favor of ICS for both effectiveness parameters even after a rigorous sensitivity analysis was performed. CONCLUSION: Based on SFD and QOL, this analysis shows that from the perspective of third party payers ICS is more cost-efficacious than LTRA with and without the consideration of indirect costs in patients with persistent asthma.