The lower weight limit for infants undergoing intraoperative transesophageal echocardiography (TEE) with current commercially available probes has not been determined. A review of the literature reveals that infants as small as 1.6 kg have been studied successfully. This report describes the first intraoperative TEE reported in a 1.4-kg infant during truncus arteriosus/interrupted aortic arch repair. Successful pre- and postoperative images of the cardiac abnormality were obtained. Probe insertion was performed in this small patient after predilating the esophagus with a 14-F suction catheter.