The aim of the study is to compare the efficacy of ciclesonide versus fluticasone propionate on lung function, time to first asthma exacerbation, asthma symptoms, use of rescue medication, and quality of life in patients with mild to moderate asthma. Ciclesonide will be inhaled at one dose level once daily; fluticasone propionate will be inhaled at one dose level twice daily. The study duration consists of a baseline period (2 to 4 weeks) and a treatment period (24 weeks). The study will provide further data on safety and tolerability of ciclesonide.

Main Inclusion Criteria:

• Outpatients
• Written informed consent
• History of bronchial asthma for at least 6 months
• Good health with the exception of asthma
• Treated with inhaled steroids with a maximum daily constant dosage of 250 mcg fluticasone propionate or equivalent
• FEV1 80 - 105% of predicted

Main Exclusion Criteria:

• Concomitant severe diseases or diseases which are contraindications for the use of inhaled steroids
• COPD (i.e. chronic bronchitis or emphysema) and/or other relevant lung diseases causing alternating impairment in lung function
• Current smoking with more than 10 pack-years
• Previous smoking with more than 10 pack-years
• Use of systemic steroids 4 weeks (injectable depot steroids 6 weeks) before entry into the baseline period, or more than 2 times
• Pregnancy
• Intention to become pregnant during the course of the study
• Breast feeding
• Lack of safe contraception