Thoracic ultrasonography (US) has proved to be a valuable tool in the evaluation of the patient with shortness of breath, chest pain, hypoxia, or after chest trauma. Its sensitivity and specificity for detecting disease is higher than that of a chest radiograph, and it can expedite the diagnosis for many emergent conditions. This article describes the technique of each thoracic US application, illustrating both normal and abnormal findings, as well as discussing the literature. Bedside thoracic US has defined imaging benefits in a wide range of thoracic disease, and US guidance has been shown to facilitate thoracic and airway procedures.