This open prospective randomized parallel-group comparative study included 43 patients with moderate or severe chronic obstructive pulmonary disease (COPD). The patients of active working age were referred to the disability groups II-III based on the average forced expiratory volume in 1 second (1.70+/0.43 1 or 49.1+/-10.7% the normal value) and received an eight-week course of pulmonary rehabilitation. During the study, the patients were given tiotropium bromide (TB) for 14 weeks to assess its effect on the tolerance of physical activity. A combination of TB with pulmonary rehabilitation was shown to improve tolerance evaluated by whole-body rheography (WBR) in a 6 minute step-test and the standard functional test. Also, this treatment resulted in the clinically significant alleviation of dyspnea and permitted to decrease the intake of salbutamol (used "as required") compared with pulmonary rehabilitation alone. It is concluded that combination of TB and pulmonary rehabilitation provides an effective tool for the treatment of patients with COPD. The whole-body rheographic technique can be used to evaluate the functional state of the patients and the efficiency of their rehabilitation.