We conducted a comparative case-control analysis of stomach cancer and atrophic gastritis involving 427 cases with stomach cancer, 1414 cases with atrophic gastritis, and 3014 control subjects based on a questionnaire survey conducted for the subjects who received gastroscopic examination at Aichi Cancer Center Hospital from April 1985 to March 1989. The risk of atrophic gastritis in both males and females was not associated with any environmental factors. The risk of stomach cancer compared with the control subjects was positively associated with an intake of salted fish guts or cod roe [relative risk (RR) = 1.52, 95% confidence interval (CI) = 1.08-2.15] and smoking (RR for 20 or more cigarettes per day = 2.84; 95% CI = 1.79-4.51) and inversely associated with Western-style breakfast (RR = 0.68; 95% CI = 0.48-0.96) in males. Additionally, the risk of stomach cancer was inversely associated with a daily intake of raw vegetables (RR = 0.56; 95% CI = 0.34-0.94) in males when compared with the patients with atrophic gastritis as controls. Several environmental factors, such as intake of green-yellow vegetables, fruit, and meat, and a family history of stomach cancer, were only associated with intestinal types of cancer in females, whereas a clear difference between diffuse and intestinal types was not observed in males. The results of the present study suggest that risk factors for stomach cancer may be different from those for premalignant lesions.