Background: Coronavirus -19 (COVID-19) infection is associated with increased mortality and long-term complications. Aim: Comparison between neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) and red cell distribution width (RDW) in their role in mortality detection. Methods: A retrospective cohort study collecting data from medical records of 114 patients admitted to the quarantine hospital intensive care unit at Ain-Shams University due to COVID-19 infection. Data was collected regarding demography, comorbidities, and length of hospital stay. Blood samples were withdrawn including complete blood count and c-reactive protein. RDW was recorded, and NLR and PLR were calculated. Patients were divided according to their outcome into cases including 57 patients who died and controls including 57 survivor patients with a comparison between both groups. Regression analysis was performed to detect predictors of mortality. Results: The mean age of the study population was 73.61 and more than half of them were males. Diabetes mellitus and bronchial asthma were more prevalent in cases. By univariate regression analysis diabetes, Mellitus and NLR were associated with increased mortality. By multivariate analysis, NLR is the only factor predicting mortality. NLR >12.4 had 57.89% sensitivity and 78.95% specificity for predicting mortality. Conclusion: NLR is the best inflammatory marker included in the study and is associated with increased mortality in severe and critical COVID-19 patients. Diabetes mellitus is associated with increased mortality in those patients.