[Purpose] We aimed to analyze parameters of pulmonary function and physiological, psychological, and physical factors in patients with chronic obstructive pulmonary disease (COPD) receiving pulmonary rehabilitation (PR) and music therapy (MT). [Participants and Methods] This randomized crossover comparative study included in-patients diagnosed with COPD and a ratio of forced expiratory volume measured at the first second and forced vital capacity (FEV1/FVC) of <70% after administration of a bronchodilator. Patients were randomly divided into two groups that received either PR only or MT and PR (n=13 each). The PR program included conditioning, respiratory muscle training, and endurance training, whereas the MT program included vocal, singing, and breathing exercises using a keyboard harmonica. The programs lasted 8 weeks, in which pre- and post-intervention data were compared every 4 weeks. [Results] The FEV1/FVC in the MT group improved after the intervention. Expiratory volume control was obtained better with feedback by sound than with expiration practice. In the MT and PR program, it was easier to adjust the timing and volume of breathing, obtain expiratory volume control, and, thus, improve FEV1/FVC than in conventional practice. [Conclusion] Combining MT with PR improves parameters of pulmonary function in patients with COPD. Music therapy is a novel approach that, in combination with PR, may be used in COPD management.