Objective: The objective of this study was to assess the cost-effectiveness of ciclesonide versus fluticasone in adult patients with mild, moderate, and severe asthma. Methods: A decision tree model was developed to simulate the health consequences and costs associated with daily asthma medication use. Patients were assumed to receive either ciclesonide or fluticasone. Potential health consequences for patients in the model included an adverse drug event (ADE) and symptom-free (SF) day. Costs included those associated with drug acquisition, the use of rescue medication, and medical resource utilization due to ADEs or non-SF days. The efficacy of ciclesonide and fluticasone was estimated using data from multiple clinical trials and data on file at Sanofi-Aventis. Data on medical resource utilization following ADEs and costs were estimated from published literature. Parity in the cost of ciclesonide and fluticasone was assumed. The model was used to calculate total daily costs, probability of an ADE-free (ADEF)/SF day, and the incremental cost per ADEF/SF day for ciclesonide versus fluticasone. Results: The use of ciclesonide is associated with lower costs ($2.01 vs. $2.02) and higher probability of an ADEF/SF day (0.254 vs. 0.247) than fluticasone, indicating that ciclesonide dominates fluticasone in the treatment of patients with varying asthma severity. Results of a one-way sensitivity analysis of all model parameters suggest that the model is most sensitive to changes in the probability of a symptom-free day on treatment with fluticasone. A two-fold increase in the cost of ciclesonide yields an ICER of $88.38 per ADEF/SF day. Conclusion: Ciclesonide produces more ADEF/SF days than fluticasone and therefore dominates fluticasone when drug prices are equal.