Asthma and Chronic Obstructive Pulmonary Disease (COPD) are major respiratory health problems. Asthma and COPD are typically characterized as different diseases with unique epidemiological features as well as pathophysiological mechanisms. Methodology- The study was conducted at tertiary care centre from 1st December 2020 to 30th May 2021. Patients diagnosed with asthma or COPD presenting to Pulmonology OPD were included in the study. 100 patients fulfilling the inclusion criteria were included for the study and further divided into two groups i.e. 50 patients each with COPD and asthma were included in the group. These subjects were again categorized into only asthma, only COPD and ACO according to GOLD and GINA guidelines. Spirometry and radiological findings were recorded along with obstructive pattern and its reversibility after administering bronchodilator. The six-minute walking test was used to record the desaturation on exertion. Result- 18% of the subjects with asthma were diagnosed with ACO and 24% with COPD. Cough was most common presenting complaint in ACO, followed by expectoration, dyspnea and wheeze. Obstruction with FEV1/FVC less than 0.7 was seen in majority of the patients with ACO. Conclusion- The reversibility with bronchodilator was significantly higher than that of COPD group. The desaturation in study subjects on six minute walking test was significantly more in ACO. However, it was less compared to COPD group