The aim of the study is to compare the effects of ciclesonide inhaled at one dose level twice daily versus fluticasone propionate inhaled at one dose level twice daily versus placebo, on short-term lower leg growth in prepubertal children with mild persistent asthma. The study duration consists of a baseline period (2 weeks), a treatment period (2 weeks for each treatment), and a wash-out period (2 weeks). The study will provide further data on safety and tolerability of ciclesonide.