The relationship between coffee drinking and the risk of bladder cancer was analyzed within the framework of a French hospital-based case-control study conducted between 1984 and 1987, which included 690 cases of histologically confirmed bladder cancer (599 males and 91 females), and 690 age-, sex- and hospital-matched controls. To dissociate the effects of smoking and coffee drinking among males, the analysis of the male group was restricted to 2 contrasted subgroups: non-smokers on the one hand, and current smokers and inhalers of black tobacco cigarettes on the other. Coffee drinking was found to be significantly associated with the risk of bladder cancer among men in both groups and the increase in the risk was dose-dependent (OR = 1, 2.9, 5.1 respectively, for drinking 1, 2, greater than or equal to 3 cups of coffee per day among non-smokers, and 1, 2.5 and 3.0 respectively, for drinking 1-4, 5-7, greater than cups among smokers). This result was not observed for women.