Background: In COPD patients the systemic inflammatory cytokines were increased and these inhibits the synthesis or secretion of TSH and peripheral conversion of T4 to T3, this leads to endocrine dysfunction in the form of hypothyroidism. Hypothyroidism causes alveolar hypoventilation, upper airway obstruction, Diaphragmatic dysfunction and respiratory failure. Altered endocrine function worsen the clinical manifestations of COPD and increases exacerbation frequency. Aims/Objectives: To assess the prevalence of thyroid dysfunction and clinical features of thyroidin COPD patients and to measure the relationship with COPD severity. Methods: 100 patients were collected from NMCH Hospital Kota. undergo Pulmonary function test, for 3 times at every 15 minutes interval and best of 3 readings were taken. The Forced Vital Capacity (FVC), (FEV1), FEV1/ FVC ratio were recorded. Blood sample was sent to check thyroid profile. Result: Out of 100 cases male patients (n=78), female (n=22). Most of patients in the age group of 51-70 (n=80). Hypothyroidism found in (n=53). overt hypothyroidism in 38, subclinical in 15. The mean TSH value is 10.35±1.72 and P-value is 0.0021. The correlation coefficient of FEV1 and TSH is -0.8305. that is good negative correlation. Means hypothyroidism was found in more severe COPD patient. Conclusions: Hypothyroidism is present in COPD, especially in severe form of COPD. Hypothyroidism not only increases COPD exacerbation but also affects the quality of life. Hence COPD patients should be regularly monitored for abnormal thyroid function and managed accordingly to improve their quality of life.