Background: Dyspnea, fatigue, and decline in sleep quality are symptoms of chronic obstructive pulmonary disease (COPD). Pulmonary rehabilitation programs have been shown to ameliorate dyspnea and fatigue. However, only a few studies have investigated the effects of pulmonary rehabilitation on the sleep quality of COPD patients. In this study, we analyzed the benefits of a pulmonary rehabilitation program to sleep quality and daytime somnolence in COPD patients. Methods: This study was a study of 30 moderate-severe COPD patients. All patients were evaluated by a pulmonologist and underwent polysomnography before participating in the study. For this study, we selected only ex-smokers and patients with sleep apnea were referred to the sleep clinic. These participants were prospectively recruited and not selected based on program completion. Before the start of the program, sleep quality and daytime somnolence of the participants were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS), respectively. Rehabilitation program consisted of muscular training sessions conducted at the gym 3 times per week for 12 weeks. After rehabilitation program, the patients were reassessed and their sleep quality and daytime somnolence were reevaluated using the PSQI and the ESS, respectively. Results: Before rehabilitation, PSQI evaluation revealed that 73% of the participants had poor sleep quality, and ESS evaluation showed that 86.7% of the participants experienced daytime somnolence. After pulmonary rehabilitation, the PSQI specifically improved in terms of subjective sleep quality and sleep duration (< 0.001), habitual sleep efficiency (0.001), and sleep latency and sleep alterations (0.002) and there was also improvement in the ESS (< 0.001). Conclusion: Pulmonary rehabilitation program of gradually increasing intensity has the potential to provide sleep-related benefits to patients with COPD who have poor sleep quality and daytime somnolence. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC) RBR62b4z2.