Transesophageal echocardiography (TEE) has recently become a major diagnostic tool in aortic disease. By far the most important role of TEE is in the rapid diagnosis of acute aortic dissection. In this disease the sensitivity and specificity of TEE are both well more than 90%, patient risk is minimal, and the test can (and should) be done in the emergency department. Limitations of TEE include, in some cases, difficulty delineating involvement of the proximal arch, major branch vessels, and abdominal aorta. Another emergency department application of TEE is the assessment of patients suspected of traumatic aortic rupture. TEE also is being applied to the diagnosis of aortic protruding atheromas, thought to have significant embolic potential.