Objectives: Despite its low sensitivity for the interstitial syndrome, chests X-Ray (XR) have been used on COVID-19 patients to exclude alternative diagnoses. Computed tomography (CT) scans can both exclude other pathological conditions and display a high level of sensitivity for the COVID-19 pneumonia. We therefore decided to compare the performance of lung ultrasonography (LUS) with that of lung CT scans in suspect or confirmed COVID-19 patients for the presence of interstitial pneumonia and the degree of lung injury. Methods: In a cross-sectional clinical study, LUS an CT were compared for the presence of interstitial pneumonia and the degree of lung injury in COVID-19 patients. Pearson’s and Spearman correlations analysis were performed to measure the degree of association between two methods. Bland–Altman plot was generated to provide a graphical visualization of the agreement between the two measurement methods. All statistical tests in this study were two-sided and p-values ≤ 0.05 were considered as statistically significant. Results: A good correlation between LUS and CT scan was obtained for estimates of lung injury in pneumonia in a group of COVID-19 suspect and diagnosed patients (R 2= 0.7613; p <0.01). Agreement between LUS and CT values is assessed by constructing Bland-Altman plot. Conclusions: LUS, as compared to CT scans, is an effective method to estimate degrees of lung injury in COVID-19 patients in the emergency department.