We investigated the anti-carcinogenic effects of a cyclooxygenase-2 inhibitor (Celecoxib) and immunosuppression drugs - Sirolimus (SIR) and Cyclosporine (CsA) - on a rat model of bladder cancer induced by N-butyl-N(4-hydroxibutil)nitrosamine (BBN). There was a statistically significant reduction in the incidence of bladder tumors in the SIR (2 mg/kg/day) and CEL (10 mg/kg/day) groups (37.5 and 12.5%. respectively: p<0.05) vs BBN (65%). with less aggressive histological changes, together with significantly lower levels of TGF-beta 1 and a better redox status (MDA/TAS). SIR 1 mg/kg/day induced a higher nr of tumors. CsA showed no significant effect on bladder carcinogenesis. In conclusion. both Sirolimus (2mg/kg/day) and Celecoxib treatments showed chemopreventive properties for urothehal bladder tumors in rats.