Background: Exercise tolerance and health-related quality of life (HRQL) are enhanced in patients with chronic obstructive lung disease (COPD) by pulmonary rehabilitation. Aim of the study: this study aimed to evaluate the effect of PR program both short and long course among stable COPD patients to improve their tolerance and outcome. Patients and Methods: This non randomized clinical study was carried out at Chest Disease Department at Pulmonary Rehabilitation Unit of Zagazig University Hospitals on 30 Stable COPD patients during the period from July 2023 to February 2024 to assess the effect of PR program both short and long course among stable COPD patients to improve their tolerance and outcome. Results: There is a significant improvement in pulmonary function tests (FEV1/FVC, FEV1, FVC) (predicted %), Oxygen saturation, 6MWD and Quality of life score after long PR course compared to short PR course. Also there was significant decrease in mMRC after long PR course compared to short PR course. Conclusions: Pulmonary Rehabilitation program should be conducted for all COPD patients , , improving dyspnea, exercise tolerance, and quality of life and. For best results exercise should continued for long course of Pulmonary Rehabilitation.