The number of lymph nodes with metastases is known to be an important prognostic factor in carcinomas of many organs. The insufficient sampling of lymph nodes has also been associated with worse outcome in several types of carcinoma. However, the prognostic significance of lymph node dissection is not well characterized in extrahepatic bile duct (EBD) carcinomas. For 209 patients with EBD carcinoma, the total number of retrieved lymph nodes and the number of metastatic lymph nodes were evaluated, and other clinicopathologic variables were correlated with patient survival. The number of retrieved lymph nodes was not significantly correlated with survival in this study. The presence of metastasis to lymph nodes significantly decreased survival of patients with EBD carcinoma. The patients with 5 or more metastatic lymph nodes had significantly worse survival than those with 4 or less metastatic lymph nodes. To evaluate the prognosis of the patients with EBD carcinomas more precisely, the number of metastatic lymph nodes as well as the status of metastasis to lymph nodes should be examined and reported. Based on the present data, we propose that nodal classification should be divided into N1 (metastasis in 1 to 4 regional lymph nodes) and N2 (metastasis in 5 or more regional lymph nodes).