In south Louisiana, 391 recently diagnosed gastric cancer patients and an equal number of controls were interviewed. Questions asked covered residential and occupational histories, environmental exposures, tobacco use, diet, alcohol consumption, and pertinent demographic characteristics. Elevated relative risks were found for use of tobacco and alcohol products. Diet was found to be the main determinant of gastric cancer risk in south Louisiana. Both dietary patterns and dietary risk factors differed for blacks and whites, although fruits as a group and dietary vitamin C were found to exert strong protective effects for both blacks and whites. Consumption of smoked foods and homemade or home-cured meats increased risk of gastric cancer for blacks but not for whites. The findings are discussed in the light of the prevailing etiologic hypotheses.