A hospital-based, case-control study of 531 male and 144 female matched pairs was conducted in Germany to analyze the role of nonoccupational and occupational risk factors in the etiology of tumors of the lower urinary tract (bladder cancer). Smoking of cigarettes was associated with an odds ratio (OR) of 3.6 for men and 3.2 for women, compared with not smoking and showed a significant dose- and time-response relationship for both sexes. Heavy pipe smoking significantly increased the risk (OR = 1.9 in men), and smoking of cigars did not alter the risk of bladder cancer. Controlling for smoking, a significantly twofold or more increase in risk was found for heavy consumption of coffee in both sexes and for heavy intake of beer in males. Increasing levels of total fluid intake were associated with increasing, smoking-adjusted risks in men. Significant associations were found for chronic infection of the lower urinary tract (OR = 1.8), familial history of bladder cancer (OR = 2.5), and frequent consumption of high fat meals (OR = 1.4) among men and for frequent consumption of canned food in both sexes (OR = 1.7 for males, 2.4 for females). With regard to occupational history, significantly elevated odds ratios were found for ever-employment in the printing (5.0), plastics and synthetics (2.6), rubber (2.5), mining (2.0), and dyestuffs (1.9) industries, for exposure to spray paints (2.9), zinc (2.3), chromium/chromate (2.2), oils (1.5), petroleum (1.4), stone dust (1.4) and metal dust/fumes (1.3), and for occupation as mining worker (2.0) and truck driver (1.8) among men. Multivariate logistic regression analysis showed significant contribution of coffee and beer drinking, ingestion of canned food, and familial occurrence of urothelial tumors to the risk of bladder cancer in men after accounting for the effects of tobacco smoking, occupational exposures, and a history of bladder infection. These other variables did not influence the risk attributable to occupational exposures.