The aim: This study was targeted to see the correlation between D-Dimer level and severity of lung injury evaluated by CT scan to prevent major complications in early of disease. Materials and methods: This study was carried out in Al-Mawani Teaching Hospital in Basra – Iraq. The study took place between August to October 2020 included 74 patients from both genders; all patients were admitted to the hospital and serial of investigations were done inform of CT scan, blood chemistry and D-dimer along with vital signs and demographic data were taken at the time of admission. Results: The correlations between the D-Dimer level and lung damage assessed by CT scan were significantly related with a P-value of less than (0.05) and regression coefficient of (3.016). Age and gender relation with severity of lung involvement were statistically non-significant. All the patients included were beyond surgical classification of ASA. Conclusions: In COVID-19 infected patients, the Severity of lung injury assessed by chest computed tomography is positively correlated with D-Dimer levels, and it can be considered as an independent predictor of severe cases.