Tiotropium is a potent, long-acting, selective anticholinergic bronchodilator. Treatment with tiotropium produces sustained improvements in lung function, particularly FEV1 (peak, trough, average, and area under the curve) compared with either placebo or ipratropium in patients with moderate to severe COPD. Preliminary evidence suggests that treatment with tiotropium may slow the rate of decline in FEV1, but this finding awaits confirmation. Tiotropium reduces lung hyperinflation, with associated improvements in exercise capacity. Tiotropium, compared with either placebo or ipratropium, improves a variety of patient-centered outcomes, including subjective dyspnea ratings and HRQL scores. Tiotropium reduces the frequency of COPD exacerbations and of hospitalizations due to exacerbations, but has not been shown to reduce all-cause mortality. Compared with the long-acting bronchodilators, tiotropium provides incrementally better bronchodilation, but it is not clearly superior in terms of patient-centered outcomes. Tiotropium has a good safety profile; however patients with severe cardiac disease, bladder outlet obstruction, or narrow angle glaucoma were excluded from all studies. Medico economic analyses suggest that treatment with tiotropium may also be cost-effective, primarily by reducing costs associated with hospitalizations.