We aimed to investigate bladder cancer risk with reference to polymorphic variants of cytochrome p450 (CYP)1A1, CYP1B1, glutathione S-transferase (GST) M1, and GSTT1 genes in a case control study. Polymorphismswere examined in 114 bladder cancer patients and 114 age and sex-matched cancer-free subjects. Genotypes weredetermined using allele specific PCR for CYP1A1 and CYP1B1 genes, and by multiplex PCR and melting curveanalysis for GSTM1 and GSTT1 genes. Our results revealed a statistically significant increased bladder cancerrisk for GSTT1 null genotype carriers with an odds ratio of 3.06 (95% confidence interval=1.39-6.74, p=0.006).Differences of CYP1A1, CYP1B1 and GSTM1 genotype frequencies were not statistically significant betweenpatients and controls. However, the specific combination of GSTM1 null, GSTT1 null, and CYP1B1 codon 119risk allele carriers and specific combination of GSTM1 present, GSTT1 null, and CYP1B1 432 risk allele carriersexhibited increased cancer risk in the combined analysis. We did not observe any association between differentgenotype groups and prognostic tumor characteristics of bladder cancer. Our results indicate that inheritedabsence of GSTT1 gene may be associated with bladder cancer susceptibility, and specific combinations ofGSTM1, GSTT1 and CYP1B1 gene polymorphisms may modify bladder cancer risk in the Turkish population,without any association being observed for CYP1A1 gene polymorphism and bladder cancer risk.