Background: Most individuals inflicted with COVID-19 present with pneumonia. Chest computed tomography is such a promising and feasible technique of diagnosis. Aim: Evaluation of the diagnostic precision of chest CT in identification of COVID-19 related pneumonia and assessment of severity in relation with ABO blood grouping system. Patients and methods: This cross-sectional analytical research performed on 60 patients with symptoms suggestive of COVID-19 related pneumonia presented to Radiology Department in Al-Ahrar Teaching Hospital from August 2020 till February 2021. Results: As regard ABO system, it was group A in 24 patients (40%), group B in twenty individuals (33.3%), group AB in 6 individuals (10%) and group O in 10 individuals (16.7%). As regard Rh system, there were 21 Rh positive patients (35%) and 39 Rh negative patients (65%) in all studied patients. The most common symptom was cough in 42 patients (70%). Regarding the diagnostic performance of chest CT for COVID-19, 48 individuals (80%) were true positive, 10 individuals (16.7%) true negative, 1 patient (1.7%) false positive and 1 patient (1.7%) was false negative. Thus, chest CT had the sensitivity of 98%, specificity of 90.9%, PPV of 98%, NPV of 90.9% and precision of 96.7%. Conclusion: In the absence of negative nucleic acid test outcomes, clinical diagnosis of COVID-19 infection may be possible via CT characteristics. Clinical practice currently relies irreplaceably on CT for diagnosis, screening, and monitoring the efficacy of treatments, as it is exceptionally sensitive to COVID-19 lesions.