Coronavirus Disease 2019 (COVID-19) is a respiratory condition that has the potential to result in thrombotic diseases. High D-dimer value is a prospective marker for undesirable prognosis in COVID-19. Aim of the study: Establishing D-dimer optimum cut-off value and using it as a predictor of mortality at admission. Materials and methods: A cross section record-based study was done on (252) COVID-19 pneumonia cases at Al-Bashir hospital, Amman, Jordan. Demographic, clinical, laboratory data and outcomes were extracted from the patients’ files. Results: Higher D-dimer group showed significantly higher death rate (76.6%). For the D-Dimer level, the Roc curve resulted in a 2.25 µg/ml cut-off point for predicting patient mortality where Specificity is 61%, sensitivity 84.21%, and AUC 79.5 % (Area Under Curve). a high D-Dimer level at admission, patients with renal disease, and shorter period of hospitalization were associated with high odds of mortality rates by multivariate regression. Conclusion: High admission D-Dimer value was a predictive of high mortality rate, especially in individuals with comorbid conditions.