Background: Severe Covid-19 infection resulted in high death rates globally, however, the predictors of mortality had been varied widely regarding their significance or effects due to different viral mutations, settings, or subjects. Aim of Study: To identify the predictors of mortality in patients with severe Covid-19 who were admitted to the intensive care unit. Patients and Methods: An observational, prospective cohort study was conducted on 231 consecutive COVID-19 patients admitted to ICU, where we compared the data for survivors versus the non-survivors, and our primary end point was death or discharge. Results: Fifty-one patients (22%) were non-survivors, where they had significantly more comorbid conditions, abnormal WBC count, lymphopenia, increased ESR and CRP, impaired renal function, and hyperbilirubinemia; while in multivariant analysis using the Cox regression model, the higher levels of total bilirubin, and low counts of WBCs were independently associated with higher mortality among cases after adjustment of confounders with p-value 0.001 and 0.040 respectively. Conclusion: Hyperbilirubinemia due to direct or indirect liver injury in patients with severe Covid-19 in addition to inappropriate response of WBC to the infection constituted the predictors of mortality in our cohort.