Introduction- COVID -19 now become pandemic disease and Chest computed tomography (CT) has very important role in diagnosis and characterizing the Covid patient severity by CT severity score. Objectives: The main purpose of this study was to evaluate the performance of MDCT in identifying & categorising the severity of COVID-19 inpatients. Methods: This is retrospective cohort study and is performed on about 512 hospitalized COVID19 patients in IGIMS from 15 April to July 2021. The CT severity score was assessed by two independent radiologists by involvement of percentage of area of each lobe of both lung parenchyma on HRCT lung. All admitted RT-PCR positive patient whose HRCT chest done in IGIMS were included in this study and OPD RT-PCR positive patient (COVID positive) & RTPCR positive (COVID positive) patient with previous history of chronic lung disease, Tuberculosis, Lung mass, bronchiectasis etc were excluded in this study