Background and aims: We investigate the impact of blood glucose on mortality and hospital length of stay (HLOS) among COVID-19 patients. Methods: Retrospective study of 456 patients with confirmed COVID-19 and glycemic dysregulation in the New York City area. Results: We found that impaired glucose adjusted for other organs systems involved (OR:1.87; 95% CI:1.36-2.57, p < 0.001), increased glucose nadir (OR:34.28; 95% CI:3.97-296.05, p < 0.01) and abnormal blood glucose levels at discharge (OR:5.07; 95% CI:2.31-11.14, p < 0.001) were each significantly associated with increased odds for mortality. New or higher from baseline insulin requirement during hospitalization (OR:0.34; 95% CI:0.15-0.78; p < 0.05) was significantly associated with decreased odds for mortality. Increased glucose peak (B = 0.001, SE=<0.001, p < 0.001), new or higher from baseline insulin requirement during hospitalization (B = 0.11, SE = 0.03, p < 0.001), and increased days to dysglycemia (B = 0.15, SE = 0.04, p < 0.001) were each significantly associated with increased HLOS. Increased glucose nadir (B = -0.67, SE = 0.07, p < 0.001), insulin intravenous drip (B = - 0.10, SE = 0.05, p < 0.05), and increased proportion days endocrine system involved (B = -0.25, SE = 0.06, p < 0.001) were each significantly associated with decreased HLOS. Conclusion: Glucose dysregulation adversely affects mortality and HLOS in COVID-19. These data can help clinicians to guide patient treatment and management in COVID-19 patients. (C) 2022 Diabetes India. Published by Elsevier Ltd. All rights reserved.