Introduction: Mortality rates of coronavirus disease increased across the world, most patients who hospitalized with covid-19 had good prognosis while a few died. In this study we are going to show that if the Laboratory abnormalities of Renal, Hepatic, Inflammation, Biochemical, Cell blood count, VBG, Cardiac, and Coagulation, before the beginning of drug treatment is death risk factors for COVID-19 patients. Method: This retrospective cohort study performed on 845 Covid-19 patients, hospitalized in Imam Hossein hospital, Tehran, Iran. Demographic & laboratory were collected by Continuous sampling method from HIS. For data analysis, SPSS 26 software and Chi-square, Fisher's exact, univariable & multivariable logistic regression were used. Result: Total hospitalized patients were 845 (643 alive, and 202 death). Logistic regression showed that laboratory data such as renal enzyme, Na, Ca, Coagulation, Cell Blood Count , VBG & cardiac enzyme such as CPK, and Troponin were associated with death, while hepatic; Ck-mb, LDH, ESR, CRP, Mg, K, and platelet were not associated. Conclusion: In this study we found that increased of the level of WBC, BUN, Cr, Na, PT, INR, CPK, & Troponin and decreased of lymphocyte level on admission were associated with increased risk of mortality due to COVID‐19 infection and these are most important predictors of mortality in hospitalized COVID‐19 patients.