Mediastinal lymphography was carried out preoperatively upon 15 patients with carcinoma of the thoracic part of the esophagus. The tracheal bifurcation was punctured, and contrast medium was slowly injected. Mediastinal lymphograms were taken within 24 hours and, again, three and seven days after this injection. The paratracheal lymph nodes were demonstrated in almost all of the patients, and a filling defect was observed in three patients, leading to possible metastatic involvement. In seven patients, the right pulmonary hilar lymph nodes were demonstrated, and no node was considered to be metastatic. In three, paraesophageal lymph nodes were preoperatively diagnosed as metastatic. All seven lymph nodes in which metastasis was suspected were confirmed to be metastatic at pathologic examination. The smallest node correctly assessed as metastatic was 6 by 6 millimeters.