The relation between alcohol consumption and the subsequent occurrence of the five most frequent cancers in Japanese men in Hawaii (cancer of the stomach, colon, rectum, lung, and prostate) was analyzed in a prospective study of 8006 subjects. Information on alcohol consumption was obtained through interviews in the mid-1960s, and the cohort has been followed since then. The analysis, which was adjusted for the effects of age and cigarette smoking, revealed a positive association between consumption of alcohol and rectal cancer, accounted for primarily by an increased risk in men whose usual monthly consumption of beer was 500 oz (15 liters) or more (relative risk, 3.05; P less than 0.01, as compared with those who did not drink beer). A significant positive relation between alcohol consumption and lung-cancer incidence was also found, accounted for primarily by an increased risk among subjects who consumed larger amounts of wine or whiskey, as compared with the risks among nonconsumers of these beverages (relative risk, 2.19, [P = 0.03] and 2.62 [P less than 0.01], respectively). No significant relation between alcohol consumption and the incidence of the other three cancers was found.