The occupations and life-style factors of 531 male bladder cancer patients were compared with matched hospital controls; risk estimates were obtained as odds ratios of discordant pairs. The case-control study as a "fishing approach" for occupational risk factors has proven successfully that established hazards for cancer could be confirmed (e g smoking, bladder infections, mining and chemical exposures), and others were identified for the first time in Germany (vehicle driving, spray painting, oil- and petroleum exposures). Not only could smoking-adjusted risk estimates be statistically confirmed but also trends of risk increasing with duration of occupational exposure were determined. Logistic regressions were performed to determine the influence of life-style factors on occupational risks.