Removal of a cardiac myxoma can be complicated by mitral stenosis, arterial embolism and so on, all of which may be life-threatening but difficult to diagnose. We describe the use of transesophageal echocardiography (TEE) for the anesthetic management of two patients undergoing removal of a large myxoma in the left atrium (LA). The first case is a 78-yr-old woman, who was suffering from cardiac cachexy with a large LA myxoma. The anesthetic management of her surgery required the prevention of a decrease in cardiac output caused by anesthetic agents, massive bleeding and surgical procedures. The second case is an asymptomatic 60-yr-old man with LA myxoma, which appeared adherent to the mitral orifice in diastole. The goal of the anesthetic management of him was to prevent the obstruction of transmitral blood flow caused by the decrease in preload on the heart. Throughout the surgeries, TEE monitoring was conducted and helped decide the doses and/or rate of inotropes and vasodilators as well as the transfusion of fluid and blood to obtain stable circulatory conditions. It was also found to be of considerable value in understanding the pathophysiology of the tumors in LA. In conclusion, TEE monitoring during the surgery can be of much use both in the diagnosis and the anesthetic management of a patient with a large LA myxoma.