Ultrasound examination is a valuable method in diagnosis of various thoracic conditions including pleural or pericardial effusion, empyema, pneumothorax, pulmonary embolism, pneumonia, and primary or metastatic lung cancer. Ultrasound guidance during thoracentesis or tube thoracostomy assures minimal complications. It can also assist with staging of lung cancer by defining the extension of thoracic wall invasion or by real-time ultrasound-guided biopsy of a supraclavicular lymph node. Invasive procedures such as mediastinoscopy can be spared with effective use of endoscopic or endobronchial ultrasound in cancer diagnosis. Intensivists are able to provide better bedside care efficiently with a focused examination in critically ill patients. Thoracic ultrasound is mostly used to locate a target organ or a disease-specific condition and is often used as a complement to other imaging such as chest radiograph, computed tomogram or magnetic resonance imaging. Advantages include portability permitting bedside examination even in the intensive care units. Specific focused skills can be easily learned with formal didactic lessons and supervised training.