Introduction and research objective: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition characterized by chronic respiratory symptoms due to airway abnormalities that cause permanent, often progressive airflow obstruction. Pulmonary rehabilitation is an important factor in the treatment of patients suffering from COPD, and the aim of this research is to investigate the effect of pulmonary rehabilitation, which will be achieved through specific objectives: analysis of the walking distance, symptoms of shortness of breath (dyspnea) and on the quality of life of patients with COPD. Also, the influence of demographic variables, body mass index and smoking status on the results of walking distance in patients will be analyzed. Subjects and methods: Subjects are patients suffering from COPD who attended the pulmonary rehabilitation program at the Clinic for Pulmonary Diseases Jordanovac, University Hospital Center Zagreb, in the period from March 2024 to the end of July 2024. Specialist findings, medical histories and other data required for this research were reviewed, as well as the results of the six-minute walk test (6MWT), the BORG dyspnea scale and the CAT questionnaire before and after pulmonary rehabilitation. Results: The sample consisted of a total of 40 respondents, of which 17 were men (42.5%) and 23 were women (57.5%). The results showed a statistically significant improvement in the walking distance and quality of life after the pulmonary rehabilitation program. Reduction of shortness of breath after pulmonary rehabilitation was not proven in this study. It also has not been proven that gender, body mass index and smoking status affect the results of pulmonary rehabilitation. According to statistical data processing, younger patients, aged 45 to 64, have statistically significantly better walking distance results after rehabilitation than older patients (aged 65 to 80). Conclusion: This research concluded that pulmonary rehabilitation has a positive effect independent of demographic factors, body mass index and smoking status. Pulmonary rehabilitation did not show a positive effect on dyspnea, and the reason for this may be the limitations of this research, such as the small sample of respondents and the duration of rehabilitation.