Introduction: Respiratory illnesses were supposed to be sore for humans but considering the present day scenario critical illnesses like COVID 19 are becoming leading cause of death.But never the less antiquity of respiratory ailments can always be remembered which was governing the world of illnesses over many decades and centuries. The deadlier variants of respiratory diseases like COPD, asthma and pneumonia are ranked at the third position in leading causes of death around the globe.For dominating these disease early detection, treatment, follow up and most importantly prevention plays the key role. For diagnosing respiratory diseases Pulmonary function tests along with clinical presentations should be of utmost priority. Thus a study was designed to see effects on lungs caused by COPD, asthma and Tuberculosis coming to our institution which may lay a stepping stone towards management of these deadlier diseases in future Material and Methods: 60 individuals were enrolled in this observational study. They were categorized into three groups. a) Tuberculosis (TB) b) Asthma, c) COPD patients. FEV1, FVC, FEV1/FVC were measured by spirometer. Results: The mean ± SD levels of FVC in asthma is (2.2 ± 0.66),TB (2.37 ± 0.78) and (1.5 ± 0.58) in COPD patients. The levels of FEV1 in respiratory diseases like Asthma, TB are ( 1.92 ± 0.55), (1.92 ± 0.64) and (1.09 ± 0.45) in COPD patients. The ratio between the FEV1/FVC in Asthma, TB and COPD are ( 88.0 ± 4.52, 81.11 ± 4.64, 64 ± 6.79) respectively. In Asthma and TB the FVC and FEV1 values are indifferent with no statistically significant of (p>0.05).While comparison betweenCOPD- asthma and COPD-TB patents the FEV1 and FVC levels were changedto be statistically significant (p <0.05). Data were analyzed by student ANOVA and Bonferronis post hoc test- P value < 0.05 can be considered statistically significant Conclusion: It can be concluded that Spirometry of the patients with diseases like TB, asthma and COPD can lay a stepping stone in diagnosis and treatment outcomes of the patients if performed well within time which can benefit the society by reducing the disease burden.