In the 4th edition of General Rules for the Study of Pancreatic Cancer by the Japan Pancreas Society (JPS), published in 1993 (English version published in 1996), a system resembling the TNM classification by the Union Internationale Contre le Cancer (UICC) was adopted, based on the results of precise analysis of data from 11.317 cases of carcinoma of the pancreas registered by the JPS during the 10-year period from 1981 to 1990. We compare the two TNM classifications and staging groups, focusing on the simplicity and reproducibility of the diagnostic criteria and the reliability of predicting outcome. To compare the prognostic value of the two classification systems, we analyzed the published data on resected cases registered by Pancreatic Cancer Registration Committee of the JPS. The results showed that a major drawback of the JPS classification is that is difficult to apply and has poor repro-ducibility. Survival rates differed significantly among the four stages in the JPS classification, whereas the UICC staging system did not reflect differences in outcome among the four stages, especially between stages II and III. The prognostic value of the UICC T category is better than that of the JPS T category, whereas the N category of JPS has better prognostic value than that of the UICC system. Believing that a combination of the two systems would solve this problem, we propose a new TNM classification and stage-grouping system that draws on the merits of both. This new system may provide improvements in staging classification that will lead to the establishment of a more practical and universal staging system for ductal carcinoma of the pancreas.