Background Early identification of SARS-CoV-2 infection is important to guide quarantine and reduce transmission . This study evaluates the diagnostic performance of lung ultrasound (LUS), an affordable, consumable-free point-of-care tool, for COVID-19 screening . Methods This prospective observational cohort included adults presenting with cough and/or dyspnea at a SARS-CoV-2 screening center of Lausanne University Hospital between March 31st and May 8th , 2020 . Investigators recorded standardized LUS images and videos in 10 lung zones per subject . Two blinded independent experts reviewed LUS recording and classified abnormal findings according to pre-specified criteria to investigate their predictive value to diagnose SARS-CoV-2 infection according to PCR on nasopharyngeal swabs (COVIDpos vs COVIDneg). We finally combined LUS and clinical findings to derive a multivariate logistic regression diagnostic score . Results Of 134 included patients, 23% (n=30/134) were COVIDpos and 77% (n=103/134) were COVIDneg; 85%, (n=114/134) cases were previously healthy healthcare workers presenting within 2 to 5 days of symptom onset (IQR). Abnormal LUS findings were significantly more frequent in COVIDpos compared to COVIDneg (45% versus 26%, p=0.045) and mostly consisted of focal pathologic B-lines . Combining LUS findings in a multivariate logistic regression score had an area under the receiver-operating curve of 63.9% to detect COVID-19, but improved to 84.5% with the addition of clinical features . Conclusions COVIDpos patients are significantly more likely to have lung pathology by LUS . Our findings have potential diagnostic value for COVID-19 at the point of care . Combination of clinical and LUS features showed promising results, which need confirmation in a larger study population.