The aim of these studies was to compare the efficacy and the safety of tiotropium, delivered via Respimat Soft Mist Inhaler (SMI), a novel multi-dose, propellant-free inhaler, with ipratropium pressurized metered-dose inhaler (pMDI) in chronic obstructive pulmonary disease (COPD) patients. Two identical, 12-week, multi-national, randomized, double-blind, double-dummy, parallel-group, active- and placebo-controlled studies were performed. COPD patients were randomized to treatment with either inhaled tiotropium (5 or 10 microg) via Respimat SMI administered once daily, ipratropium (36 microg) pMDI QID or placebo. The primary endpoint was the mean trough forced expiratory volume in 1s (FEV(1)) response after 12 weeks of treatment. Secondary endpoints included other spirometry measures and rescue medication use. A total of 719 patients were randomized; the majority were male (69%) with a mean pre-bronchodilator FEV(1) (% predicted) of 40.7%. The mean treatment differences between tiotropium 5 and 10 microg and placebo for the primary endpoint (mean trough FEV(1) response at week 12) were 0.118 and 0.149L, respectively (both P<0.0001). Treatment differences between tiotropium 5 and 10 microg and ipratropium were 0.064L (P=0.006) and 0.095L (P<0.0001). The increases in peak FEV(1), FEV(1) AUC((0-6h)) and FVC for both tiotropium doses were statistically superior to placebo (P<0.01) and higher than ipratropium. All active treatments significantly reduced the rescue medication use compared with placebo, but only tiotropium 10 microg was statistically superior to ipratropium (P=0.04). The incidence of adverse events was comparable across groups. In conclusion, tiotropium 5 and 10 microg daily, delivered via Respimat SMI, significantly improved lung function compared with ipratropium pMDI and placebo.