SUMMARY. This is a review of the use of lung ultrasound (US) in routine clinical practice. Over the past few years, the use of lung US in critically ill patients has gained in popularity, and has been associated with very good outcomes. Lung US is the fastest, noninvasive, sophisticated diagnostic tool used in the Intensive Care Unit (ICU) and in other in-patient settings, free of complications and with minimal cost. It is common knowledge that the US beam cannot normally pass through air-filled structures, making the evaluation of lung parenchyma under the ribs impossible. This does not prevent the diagnosis of several abnormal conditions, including pneumothorax, consolidation, atelectasis, pleural effusion, and others. The aim of this review is to summarize the applications of sonographic imaging of the lungs and the findings associated with major respiratory disorders. Pneumon 2007; 20(2):134-141.