Transoesophageal echocardiography (TEE) is recognised as a semi-invasive technique that has an increasing impact as a diagnostic tool in anaesthesia and intensive care medicine. However, adequate assessment of TEE is based on knowledge of basic echocardiographic principles and their limitations and sufficient educational training of the user. TEE has an established role in various clinical circumstances. It often saves time-consuming investigations for the diagnosis of aortic injuries in trauma patients. It is also useful in patients undergoing cardiac valve repair or congenital heart surgery with regard to assessment of the operative success. In patients with severe hypotension TEE may identify the cause, and thereby facilitate successful patient management. Moreover, TEE has an impact on the diagnosis of endocarditis and pathologic findings within the heart and pericardial sac. TEE-associated diagnosis and decision-making may lead to an improved clinical outcome, which in turn may lead to subsequent cost reduction.