The clinical value of biplane transesophageal echocardiography (TEE) was assessed on basis of the experience of the first 100 cases. All studies were performed in awake patients, there was no complication or failure. There wee 43 males and 57 females, aged between 13 and 82 years. The indication of TEE was infective endocarditis in 33, congenital heart disease in 25, suspected tumor or thrombus in 18, search for source of embolism in 9, thoracic aortic pathology in 9, prosthetic valve dysfunction in 3 and other problems in 3 cases. Biplane technique provided additional information as compared to single plane TEE in the diagnosis of infective endocarditis (by the visualization of small vegetations and of mitral valve fenestration, and by the differentiation of mitral vegetation from prolapse or aneurysm), in the identification of source of embolism (by easier visualization of patent foramen ovale and of the left atrial appendage thrombus), in the imaging of ascending aorta, of right ventricular outflow tract and of the left ventricular endocardium. Biplane technique enhanced therapeutic decision making particularly in the indications of anticoagulant treatment and in planning certain cardiac operations. Biplane TEE is an easily acquired technique and it will replace single plane TEE in a number of indications.