Intraoperative transesophageal echocardiography (IOTEE) has become an important diagnostic and monitoring tool in the operating theatre during cardiac and noncardiac operations. However, its routine application during valve replacement operations has not received universal recognition. The cumulative experience, brought up in this review, shows that IOTEE is invaluable during valve replacement operations. It has an important role in the consolidation of operative strategy, although it is generally better to obtain all the anatomical and physiological data and the resultant operative strategy in advance, outside the operating room environment. Important data influencing the operative plan has been reported in 3-29% of operations in various studies. The postpump IOTEE is also essential for numerous reasons: it can rule out important misfortunes, such as leaflet immobilization or perivalvular leak, leaky bioprosthesis or coronary obstruction due to valve struts, and is responsible for second pump-run in 3-6% of cases; it is essential in monitoring the deairing process; it provides the surgeon and the anesthesiologist data on biventricular function and volume and exclusion of dynamic left ventricular outflow tract obstruction, and, therefore, guides pharmacotherapy, volume handling and mechanical assistance, including intra-aortic balloon pump indication and location. In conclusion, IOTEE is an essential tool in patients undergoing valve replacement operations, and should be used on a standard basis.