Previous studies have provided conflicting information on the role of tobacco and alcohol in gastric carcinogenesis. A population-based case-control study with 338 histologically confirmed gastric-cancer cases and 679 control subjects was conducted. Information relating to life-time tobacco consumption, alcohol intake and diet during adolescence and 20 years before interview, and to socio-economic conditions was obtained through face-to-face interviews. Current cigarette smokers were found to have a greater risk than non-users of tobacco. The duration of cigarette or pipe smoking was positively associated with gastric-cancer risk. There was significant interaction between tobacco use and fruit consumption. High fruit intake was more protective among users of tobacco than among non-users, and the risk estimates associated with cigarette smoking were higher among those with low fruit consumption than among frequent fruit-eaters. Likewise, though to a lesser extent, vegetable intake interacted with tobacco use. Snuff dipping and alcohol intake was not associated with gastric-cancer risk. However, high alcohol intake tended to increase the risk associated with tobacco use. This study adds further support to the role of tobacco smoking in gastric carcinogenesis, and demonstrates that high intake of fruits and vegetables may be particularly beneficial in smokers. © Wiley-Liss, Inc.