Purpose: Diabetic's patients are supposed to experience higher rates of COVID-19 related poor outcomes. We aimed to determine factors predicting poor outcomes in hospitalized diabetic patients with COVID-19. Methods: This retrospective cohort study included all adult diabetic patients with radiological or laboratory confirmed COVID-19 who hospitalized between 20 February 2020 and 27 April 2020 in Alborz province, Iran. Data on demographic, medical history, and laboratory test at presentation were obtained from electronic medical records. Diagnosis of diabetes mellitus was self-reported. Comorbidities including cancer, rheumatism, immunodeficiency, or chronic diseases of respiratory, liver, and blood were classified as "other comorbidities" due to low frequency. The assessed poor outcomes were in-hospital mortality, need to ICU care, and receiving invasive mechanical ventilation. Self-reported. Multivariate logistic regression models were fitted to quantify the predictors of in-hospital mortality from COVID-19 in patients with DM. Results: Of 455 included patients, 98(21.5%) received ICU care, 65(14.3%) required invasive mechanical ventilation, and 79 (17.4%) dead. In the multivariate model, significant predictors of "death of COVID-19" were age 65 years or older (OR (95% CI): 2.0 (1.16-3.44), chronic kidney disease (CKD) (2.05 (1.16-3.62), presence of "other comorbidities" (2.20 (1.04-4.63)), neutrophil count >/=8.0 x 10(9)/L)6.62 (3.73-11.7 ((, Hb level < 12.5 g/dl (2.05 (1.13-3.72) (, and creatinine level >/= 1.36 mg/dl (3.10 (1.38-6.98)). (All p -values <0.05). Some of these factors were also associated with other assessed poor outcomes, e.g., need to ICU care or invasive mechanical ventilation. Conclusion: Diabetic patients with age 65 years or older, comorbidity CKD, "other comorbidities", as well as neutrophil count >/=8.0 x 10(9)/L, Hb level < 12.5 g/dl, and creatinine level >/= 1.36 mg/dl, were more likely to dead after COVID-19. Presence of hypertension and cardiovascular disease were associated with none of the poor outcomes.