Background and Aim: Chronic obstructive pulmonary disease (COPD) is related to a number of comorbidities that contribute to various phenotypes, including increased mortality rates and decreased physical activity. The present study aim was to determine the incidence of obstructive sleep apnea among chronic obstructive pulmonary disease patients. Methodology: This prospective study was carried out on 250 obstructive pulmonary disease patients at the department of Medicine/ Pulmonology, Fauji Foundation Hospital, Rawalpindi and Avicenna hospital, Lahore from February 2021 to July 2021. Out of 250 patients, 128 patients were enrolled based on clinical examination, medical history and pulmonary tests. Ethical approval was taken from the respective institutional ethical committees. Written informed consent was taken from all the patients. All the patients with sputum production, history of disease exposure and risk factors, chronic cough and forced vital capacity with volume of post-bronchodilator forced expiratory presence in first capacity <70% were enrolled. Patients with thyroid dysfunction, decompensated heart failure, hepatic and renal impaired, Obstructive sleep apnea (OSA) caused by ENT, and acute COPD patients (forced vital capacity <30% or <50% anticipated were excluded. Based on BMI, COPD patients were categorized into two groups: Group-I had 64 obese patients of chronic obstructive pulmonary disease (BMI≥ 29 kg/m2) and non-obese COPD patients (BMI≤ 29 kg/m2) in Group-II. SPSS version 21 was used for data analysis. Results: Of the total 128 COPD patients, male and female patients were 84 (65.6%) and 44 (34.4%) respectively. Out of 128 COPD patients, the incidence of mild, moderate, and severe COPD was 28 (21.9%), 68 (53.1%), and 32 (25%) respectively. The severity of obstructive sleep apnea was 9 (32.1%) in mild, 28 (41.2%) in moderate, and 27 (84.4%) in severe respectively. Based on body mass index (kg/m2), incidence of mild, moderate and severe cases in Group-I (Obese) and Group-II (non-obese) were 3 (2.3%), 20 (15.6%), and 41 (64.1%) and 26 (20.3%), 33 (25.8%), and 5 (3.9%) respectively. Conclusion: Our study found that sleep-disordered breathing diagnosed in moderate and severe in COPD patients. Obstructive sleep apnea are more likely to develop in Obese COPD patients. Keywords: Obstructive sleep apnea, COPD, Obesity