Cardiac ultrasonography, in particular transesophageal echocardiography (TEE) provides high-quality real-time images of the beating heart and mediastinal structures. The addition of Doppler technology introduces a qualitative and quantitative assessment of blood flow in the heart and vascular structures. Because of its ease of insertion and ready accessibility, TEE has become an important tool in the routine management of critically ill patients, as a monitor in certain operative settings and in the aortic and cardiac evaluation of trauma patients. The rapid assessment of cardiac preload, contractility and valve function are invaluable in patients with acute hemodynamic decompensation in the intensive care unit as well as in the operating room. Because of its ease and portability, the TEE assessment of traumatic aortic injury after blunt chest trauma can be rapidly undertaken even in patients undergoing life-saving procedures. The role of TEE in the surgical and critical care setting will no doubt increase as more people become aware of its potential.