In this randomized, double-blind, placebo-controlled trial, 397 patients with moderate to severe asthma, previously treated with bronchodilators alone, received fluticasone propionate 88, 220, or 440 microg twice daily, or placebo via metered dose inhaler (MDI) for 12 weeks. Mean change from baseline to endpoint in pre-dose percent predicted forced expiratory volume in one second (FEV1) was greater (p < 0.001) in each fluticasone propionate group (9.0%, 88 microg bid; 9.8%, 220 microg bid; 11.2%, 440 microg bid) versus placebo (3.4%). Morning and evening peak expiratory flow (PEF), asthma symptoms, and supplemental albuterol use also improved in all fluticasone propionate groups versus placebo. The incidence of adverse events and 24-hour urine cortisol excretion rates were similar between active treatments and placebo.