Mate is a 'tea', made from Ilex paraguariensis, widely consumed in South America, as mate con bombilla and mate cocido. Mate consumption has been associated with esophageal, oral, lung, and bladder cancers. This bladder cancer case-control study involved 114 Argentinean case-control pairs. Mate consumption was recorded for time of interview, and 20 and 40 years previously. Mate con bombilla consumed 20 years ago was associated with bladder cancer in ever-smokers (odds ratio=3.77, 95% confidence interval: 1.17-12.1), but not in never-smokers. Mate cocido was not associated with bladder cancer. These results are consistent with a previous study in Uruguay.