Aim: It was aimed to investigate whether ultrasonographic evaluation of the lungs has a diagnostic value for COVID-19 pneumonia in patients who presented to the emergency department (ED) with symptoms suggestive of COVID-19. Materials and Methods: A prospective, cross-sectional, observational study was conducted in the Emergency Medicine Department of XXX Hospital over 2 months. A total number of 204 adult patients who presented with symptoms suggestive of COVID-19 were included in the study. The findings and results obtained from the Lung Ultrasonography (LUS) and Thorax Computed Tomography (CT) were collected. Results: 112 patients had Thorax CT findings consistent with COVID-19 pneumonia. 104 (92.86%) of them were “LUS positive”. The sensitivity of LUS in the diagnosis of COVID-19 was 93.33% and specificity was 80%, Positive Predictive Value was 82.96%, and Negative Predictive Value was 92%. Patchy B-lines was the most sensitive LUS finding. ROC analysis was performed for two different COVID-19 LUS scores: In the patient group, an “LUS score” above 13 had a 80% sensitivity and 52.63% specificity in terms of 14-day mortality. Also a “Total LUS Score” above 13 had a sensitivity of 79.46% and specificity of 57.89% for 14-day mortality. Conclusion: LUS can assist the emergency physician in triage and clinical decision-making in COVID-19. We have defined a novel COVID-19 “Total LUS Score”. This score had a better specificity, and similar sensitivity compared to “LUS Score” which was defined in the literature before, and both were found to be associated with poor clinical outcomes. Patchy B-lines (89.3%) and Pleural Thickening (63.4%) are the most common COVID-19 related findings in LUS. It is recommended to look for these two findings in patients with suspected COVID-19.