We report the usefulness of transesophageal echocardiography in evaluating a patient with sclerosing mediastinitis. The technique enabled us to identify a mass obstructing the superior vena cava and right upper and lower pulmonary veins, and infiltrating and invaginating into the left atrial cavity. Transesophageal echocardiography was superior to computed tomography and transthoracic echocardiography in delineating these findings.