Background: The disease of Coronavirus-19 is extremely transmittable and is spreading at a speedy manner. Yet still there are no currently used biomarkers that can simply determine the severity of COVID-19. The neutrophil-to-lymphocyte ratio (NLR) is one of the cutting-edge biomarkers that are used in patients with various diseases. A high NLR is expressed in COVID-19 patients with unfavorable prognosis. Early identification of COVID-19 patients who are at high risk of adverse clinical sequelae is crucial in saving their lives especially in settings of limited medical resources. Objective: This study aimed to investigate the NLR influence on prognosis and the ideal cutoff value in the laboratory-confirmed COVID-19 cases. Subjects and Methods: This is a retrospective cohort study of 100 patients with confirmed COVID-19 that were hospitalized through the period from January 10th till July 20th, 2022, in Dar-Assalam Hospital, Baghdad. Diagnosis was performed by molecular assay from nasopharyngeal swabs. Patients with more than or equal to the cutoff value of NLR   had deterioration in their clinical outcome, and classified during hospitalization to mild /moderate to severe condition. Results:  100 patients with COVID-19 were involved in the study. Advanced stages COVID-19 patients had a significant high level of NLR in comparison with earlier stages. NLR can help in the diagnosis and prediction of the prognosis of the disease, primarily mortality prediction. Conclusion: Our work showed that NLR can help in the assessment of COVID-19 severity and can support the decision-making process regarding treatment strategy by the early identification of patients with severe illness.