Transesophageal echocardiography, especially in the emerging generation of biplane and multiplane probes with the availability of continuous wave Doppler, has increased our capability for evaluating intracardiac hemodynamics and ventricular function. Transesophageal studies have expanded their role both in clinical research and routine monitoring. The available hemodynamic data (assessment of left and right ventricular function, estimation of left atrial and pulmonary artery pressures, evaluation of the hypotensive patient) apply not only to patients monitored in the operating room but also to patients in the critical care and ambulatory setting. These data can be combined with the anatomic pathology to provide bedside diagnoses and often facilitate appropriate therapy. Further improvements in the quality of both images and computer software are likely to allow more detailed studies of subtle changes in cardiac function in humans.