With transesophageal echocardiography (TEE), a new echocardiographic window is obtained which enables cardiologists to explore the heart from the esophagus and stomach. However, the procedure, when first undertaken, may present certain difficulties for the cardiologist in interpreting the anatomical findings and approaching a diagnosis. We thus convey our first experiences and results of TEE in 107 pediatric patients. Transesophageal echocardiography (TEE) was performed in 107 pediatric patients at our institution between December 1998-February 2001, using the standard techniques and following the standard criteria suggested by the American heart Association. The mean age of 54 male (50.5%) and 53 female (49.5%) patients was 7.8 years. Intubation difficulty was experienced in four cases. In one case, while drawing the transducer back from the esophagus, it kinked at the hypopharynx. None of the cases had major hemorrhage or esophageal rupture, and only a few cases had minor pharyngeal injuries or hemorrhages. We used TEE in detecting vegetations in patients with possible endocarditis, and evaluating the prosthetic valves and abnormal pulmonary venous return. We also used TEE to clarify preooperative anatomical details, postoperative complications and residual defects of complex congenital cardiac anomalies. Transcattheter closure of 47 secundum atrial septal defects (ASD)'s and a muscular ventricular septal defect (VSD) (both during patient selection and during the procedure) were accomplished under TEE guidance. As the pediatric cardiologists gain more experience in performing TEE, this technique will have a wider and more effective use in the pediatric population.