||The proportions of gastric cancer cases attributable (or attributable risks, AR) to consumption of traditional foods (i.e., pasta, rice and maize), low intake of beta-carotene and vitamin C, short duration of use of an electric refrigerator, low educational level, and family history of gastric cancer were computed using data from a case-control study conducted in Northern Italy. Between 1985 and June 1993 a total of 746 incident, histologically confirmed gastric cancer cases and 2,053 controls admitted to the same network of hospitals for acute, nonneoplastic, non-digestive-tract diseases, unrelated to long-term modifications of diet, were interviewed. The ARs were 48% for low intake of beta-carotene, 40% for high consumption of traditional foods, and 16% for low intake of vitamin C. Overall, these 3 dietary factors explained 73% of the gastric cancer cases in the population. Five percent of all cases were attributable to less than 30 years' use of an electric refrigerator, 15% to low educational level, and 5% to family history of gastric cancer. In individuals over age 60, a greater proportion of cases was attributable to traditional foods, low education and late adoption of electric refrigeration (58% vs. 32% aged under 60), suggesting that correlates of lower social class, influenced lifestyle, and dietary habits more markedly in earlier than in more recent generations. According to our estimates, over 3 quarters of the gastric cancer cases in this area are explainable in terms of the risk factors considered. Increased consumption of vitamin C and beta-carotene, and reduced consumption of traditional foods, would help to avoid over 10,000 out of 14,000 stomach-cancer deaths in Italy every year. Consequently, stomach cancer, which is still the third leading cause of cancer death in Italy, would represent only about 2% of all cancer deaths.