Introduction: SARS- CoV-2 global pandemic has fired the world into a notable health catastrophe, with over 187,348,181 cases and 4,044,898 deaths as of July 10 2021. Many studies have been conducted to determine the clinical, biological, and radiological characteristics of COVID-19 for better identification of infected people at an early stage and stop disease development to an advanced state. Objectives: The aim and objective of our study was to take advantage of the biochemical and hematological parameters in pre-dicting the prognosis and mortality in disease severity COVID-19 patients. Methods: This single-center retrospective, observational study was supervised to have all the admitted patients (n = 90) possessing COVID-19 Polymerase chain reaction (PCR) positive, and assessed those for prognosis and disease outcome by taking advantage of several biochemical and hematological markers. Results: Out of 90 patients, 53(58.89%) had mild to moderate disease that were included in the non-severe group; 37(41.11%) had severe to critical disease, of which 17 died and 20 survived. Advanced age, presence of comorbidities and infection were risk factors for advancement to severe disease. The existence of statistically significant abnormalities in the following parameters were strongly related with the advancement to severe disease: white blood cells (WBC, p=0.002), neutrophils (p=0.001), lymphocytes (p=0.001), C-reactive protein (CRP, P