The highest rate for bladder cancer in Latin America has been reported from La Plata, Argentina. A case-control study was carried out to investigate the reasons for this high rate. A total of 117 cases, 117 hospital controls and 117 neighbourhood sex- and age-matched controls were interviewed regarding their smoking and drinking habits and occupational exposures. Cigarette smoking and coffee drinking were identified as the major risk factors, and a significant association was also found for truck and railway drivers and for oil refinery workers. The relative risks for male smokers who ever smoked cigarettes vs. non-smokers was 4.3 (95% Cl: 1.9-10.3). The risk associated with black tobacco cigarettes was 2-3 times higher than that of blond cigarettes. For male ex-smokers the risk after 5 years of no smoking is less than one third of that of current smokers. The RR for drinking coffee was 2.4 (95% Cl: 1.4-4.4) after adjusting for the effects of tobacco smoking, and the risk increased with the number of cups per day. No association was found with the use of saccharin.