Ciclesonide is a nonhalogenated corticosteroid that is converted to its clinically active metabolite, desisobutyryl-ciclesonide, by esterases in the airways. Pharmacodynamic studies have shown that inhaled ciclesonide has potent antiinflammatory activity in patients with asthma, and does not appear to have clinically relevant systemic effects, even at high doses. It is highly protein-bound and rapidly metabolized by the liver, and thus has a low oral bioavailability. Ciclesonide is formulated as a solution for inhalation using a hydrofluoroalkane pressurized metered-dose inhaler. This formulation delivers a high fraction of respirable particles that yield high lung deposition with even distribution throughout the lungs and minimal oropharyngeal deposition. Results from numerous 12-week trials in patients (including children) with varying degrees of asthma show that morning or evening dosing with ciclesonide is more effective than placebo, and at least equivalent to other inhaled corticosteroids such as budesonide and fluticasone, with regard to improved spirometry, symptom scores, and less need for rescue medication. Results with once-daily ciclesonide are similar to those with twice-daily budesonide or fluticasone. At the dosages used in clinical trials, ciclesonide did not exert any untoward adverse effects and did not affect cortisol production. The favorable pharmacological properties of ciclesonide help explain the low incidence of adverse events, which are mostly mild to moderate in nature. Once-daily ciclesonide offers an efficacious treatment option for stepwise asthma management when inhaled corticosteroids are required.