Background and Objective:- Coronavirus disease 2019is ongoing epidemic with a multitute of long rangingeffecton physiological balance of the human body.It can cause several effect on thyroid function on well. We aim to asses the effect of thyroid hormones changes in Covid-19 patients diseaseseverity . Methods:-The study was conducted in the Department of Medicine, BRD Medical College, Gorakhpur with the retrorespective observational study designand duration in one year. I was taken 100 Covid-19 RTPCR positive patients of either gender age more than 18 years. Results:Out of 100 Covid-19 positive patients, 16 patientswere belong to mildgroup,50 patientsweremoderate groupand 34 patientswere severe group. Total 23 patient were expired. All expired patient were from severe group,so covid 19 disease mortality was 23%. 13 patient with low TSH value, 17 patient with high TSH value and 70 patient have normal TSH level.The disease severity of patientwith low TSH was 23% and mortality 15.3%, In normal TSH patient disease severity was 24% and mortality 15.7% , but in patient with high TSH disease severity is 82.3% and mortality 58.8% with p value (p= 0.0181).This signify that there was a strong association with covid 19 disease severity and mortality with TSH changes.