The eating habits of Japanese people are changing, which may have something to do with the increase in pancreas cancer in Japan.Chiefly from the viewpoint of the eating habits, we investigated the etiological factors of this cancer through a community-based case-control study, employing 141 cases and 282 controls (two for each case) matched for sex, age, and place of residence, and through an ecologic study using the official reports of food consumption and deaths from this cancer in Hokkaido Prefecture.The case-control study showed that intake of meats and animal viscera increased the risk of this cancer. On the other hand, vegetables and the traditional Japanese foods, e.g., tofu, deep-fried tofu, raw fish, and tempura, reduced the risk. The controls took more of the traditional Japanese foods than the cases. The ecologic study showed there were significantly negative correlations between the annual consumption of plant foods/plant protein and the annual crude mortality of pancreas cancer.The traditional Japanese foods, which include many plant foods, are preventive against the occurrence of pancreas cancer.