This report describes usefulness of intraoperative transesophageal echocardiograpy (TEE) based on 773 cases we experienced in 7 years. We assessed residual lesions, ventricular function and preload with TEE. We found a case with stenotic lesion in her lateral tunnel which TEE revealed after Fontan procedure. We also ensured that no micro air bubble was in the left ventricle and the left atrium before weaning from cardiopulmonary bypass. No patient suffered from convulsion during postoperative management after induction of intraoperative TEE examination though we had had some cases in the previous year. Respiratory compromise was observed in 3 cases (0.5%) and significant hemodynamic change occurred in 9 cases (1.3%). The conditions improved just after withdrawing TEE probe. Neither inadvertent tracheal extubation, nor serious complication occurred during TEE examinations. The incidence of complications during pediatric TEE is low and TEE examination is useful for pediatric patients with congenital heart disease.