We report two cases of complete transposition of the great arteries with pulmonary venous obstruction which was diagnosed by intraoperative transesophageal echocardiography, but was not detected by transthoracic echocardiography and cardiac catheterization. The pulmonary venous obstruction was relieved simultaneously with arterial switch operation. The intraoperative transesophageal echocardiography has great contribution for thorough evaluation of the pulmonary venous return of the patients.