Patients with thoracic esophageal carcinoma who underwent extended lymph node (LN) dissection were studied to assess the state of LN metastasis and evaluate its outcome in terms of a prognostic benefit. Pertaining to LN metastasis, it was found that depending on the location of a primary tumor, the area of choice, in which metastasis tends to develop predominantly, showed some variation. However, irrespective of the location of the tumor, the predominant growth of positive nodes was found to locate among three fields, namely the neck, mediastinum and abdomen even in patients with a single metastatic node. This suggests that extended LN dissection including the neck, mediastinum and abdomen should be considered mandatory, if a complete removal of the tumors for carcinoma of the thoracic esophagus is to be desired. Multivariate analysis revealed importance of LN dissection as a prognostic factor. A cumulative survival rate in the patients with lymphadenectomy through right thoracotomy was statistically better than that in the patients who underwent blunt extraction of the esophagus without lymphadenectomy. Furthermore, extensiveness of LN dissection could effectively serve as a prognostic factor. Consequently, three-field LN dissection yields a prognostic benefit to improve a long term survival in patients with carcinoma of the thoracic esophagus.