Intraoperative transesophageal echocardiography (TEE) has become an important monitoring device for patients undergoing repair of congenital heart disease. TEE allows preoperative assessment of ventricular volume and function, pre and postoperative anatomy and the existence of intracardiac air. Although complications associated with TEE are infrequent, interference with ventilation as a result of direct compression of the endotracheal tube, distal trachea, or mainstem bronchi has been reported. Here, we report two cases of intraoperative ventilation interference caused by the TEE probe.