Recent increase in the incidence of malignant lymphoma (ML) suggests possible involvement of lifestyle or environmental factors in its genesis. However, evidence for an effect of lifestyle factors, especially diet, on ML risk among Japanese is lacking. To explore the possibility that lifestyle factors exert an influence, we have conducted a hospital-based case-control study with 333 histologically confirmed ML cases and 55904 non-cancer controls who first visited Aichi Cancer Center Hospital between 1988 and 1997. Multiple logistic regression analysis showed regular alcohol consumption to be associated with reduced risk of ML, whereas no risk change was observed for smoking. Some other factors including intake of vegetables (carrots and pumpkin), pork and fish showed partial associations, but their significance needs further clarification. From the previous study on genetic background for ML [Matsuo et al., Blood, 97, 3205 - 3209 (2001)], genetic variation combined with limited environmental factors should be targeted in future studies.