The non-infectious diseases has become one of the most important public health problems for their rapid increase in mortality rates. Malignant neoplasm is the leading cause of deaths in Taiwan, and cancers of liver, lung, stomach are three major cancers for man. This cohort study was carried out to explore multiple risk factors of these three cancers. Study subjects of the cohort included 13, 910 men who were recruited from 12 precincts and townships in Taiwan and had been followed up for five to eight years. A structured questionnaire was used to collect the information on risk factors including demographic characteristics, cigarette smoking, alcohol drinking and dietary habits. The information on the deaths from cause of the cohort was obtained from telephone interviews, household registry and death certification system. Analysis based on Cox's proportional hazard models showed that the relative risks of developing lung cancer for those who smoked 11-20 and＞20 cigarettes per day were 4.13 and 5.67, respectively, compared with nonsmokers. The relative risks of developing liver cancer were 3.54 for those who drank alcohol＞50cc daily corn- pared with non-drinkers; 13.7 for HBsAg-positives compared with HBsAg-negative; 3.21 for those who consumed vegetable for less than six meales per week compared with those who consumed vegetable more than six meals; and 3.16 for those who had a vegetarian habit for＞10 years compared with those who had no vegetarian habit. The relative risk of developing stomach cancer was 3.06 for those who smoked 26 pack-years of cigarettes compared with non-smokers.