Background. The rapid expansion of pediatric cardiovascular surgery, along with the increase in the number of centers and operations, has also increased the use of intraoperative transesophageal echocardiography (TEE). Preoperative TEE allows for the confirmation of diagnoses established by transthoracic echocardiography and angiography, and also identifies possible additional pathologic conditions. TEE is also used to follow up on surgical repairs, determine the need for reintervention, and evaluate myocardial performance and the need for inotropic treatment. Our intention is to share the TEE findings before and after intervention for congenital heart disease in patients who received operations at our center, and the conclusions reached.