Diagnosis of pneumonia can be challenging, particularly the differential diagnosis of lower respiratory tract infection and pneumonia, acute respiratory failure, the diagnosis of nosocomial pneumonia and in case of treatment failure. As compared to conventional chest radiography and CT of the scan, sonography of the chest offers advantages. It could be demonstrated that it was even superior to chest radiography in the identification of pneumonic consolidations. Since most pneumonias affect the lower lobes and include the pleura, pneumonic substrates could be identified in up to 90% of cases despite the limited penetration depth of lung ultrasound. Sonography of the chest has become an established method in the diagnosis of both adult as well as in pediatric community-acquired pneumonia. In addition, it is particularly powerful when used within a point of care (POCUS) approach which also includes the evaluation of the heart. Finally, it appears to have significant potential also in the diagnosis of nosomomial pneumonia and in the evaluation of treatment response, both in the ward as in the ICU.