Abstract Introduction Lung ultrasound (LUS) has become the first diagnostic imaging approach to assess lung involvement in COVID-19. While LUS proved to be safe, reliable, and accurate, not many primary care physicians (PCP) are capable to employ this instrument in the first evaluation of COVID-19 outpatients. The aim of this study was to determine the effectiveness of a brief training program in LUS for PCP. Methods Italian local authorities promoted a training program in LUS for PCP engaged in COVID-19 outpatients’ evaluation. The course took place in a COVID-19 unit and included a hands-on practice on real COVID-19 patients. We conducted a qualitative and quantitative analysis of the results of the training program. Results A total of 32 PCP completed the training. About 100% of participants reported an increase in competence and confidence in the use of LUS after the training. Self-reported confidence in detecting major COVID-19 LUS abnormalities was high (B-lines 8/10, pleural abnormalities 6.5/10). B-lines were accurately identified with a reliability of 81%, with a sensitivity of 96%, and a negative predictive value of 98%. Trainees were some less accurate in detecting pleural abnormalities (reliability 63%) but with a high specificity (99%). Conclusions This study showed that a short training program, but comprising a hands-on practice, is capable to bring even almost novices to achieve a high overall accuracy and reliability in detecting lung involvement in COVID-19. This may result in a significant improvement of the performances of PCP involved in the first evaluation of COVID-19 cases in primary care facilities.