OBJECTIVES: There is scarce data available on the prognostic application of chest CT. The main purpose of this study was to evaluate the performance of a semi-quantitative CT severity score in identifying the risk of mortality in COVID-19 patients. METHODS: This retrospective cohort study was performed on 262 hospitalized COVID-19 patients. The CT severity score was assessed by two independent radiologists using a method previously used to score the severity of acute respiratory distress syndrome on thin slice lung CT. RESULTS: Multivariate regression analysis showed increasing odds of in-hospital death associated with older age, and the presence of coronary artery disease at the time of admission. The mean CT severity score was 7.5 in the survivor group and 14.5 in the deceased group. Overall, the lower zones were the most frequently affected sites in COVID-19. There was significant difference between the survivor and deceased groups regarding CT severity scores. Multivariate regression analysis showed increasing odds of in-hospital death associated with higher CT severity score at admission. CONCLUSIONS: Our results show that mortality was significantly higher in patients with higher CT severity score even after adjustment for clinical, demographics and laboratory parameters. However, this study is performed retrospectively and needs to be validated in a prospective study.