Transesophageal echocardiography (TEE) is a new application of echocardiography in which an ultrasonic transducer is positioned in the esophagus and stomach to obtain images of the heart without interference from lung and bone. It is particularly useful in the assessment of left atrial masses, atrial septal defects, mitral valve disease, valvular prostheses and aortic dissection. In the operative setting, TEE is used to detect early myocardial ischemia in patients with coronary artery disease undergoing noncardiac surgery as well as in the assessment of the results of valvular surgery. This review examines the technique of TEE, its indications and the early experience with the first 100 patients examined at the Toronto Western Hospital with this technique.