Endothelial nitric oxide synthase (eNOS), encoded by the NOS3 gene, has been suggested to play an importantrole in uncontrolled cell growth in several cancer types. The objective of this study was to evaluate the role ofthe NOS3 Glu298Asp polymorphism in bladder cancer susceptibility in a Turkish population. We determinedthe genotypes of 66 bladder cancer cases and 88 healthy controls. Genotypes were determined by polymerasechain reaction-restriction fragment length polymorphism analysis. A significant association for NOS3 Glu298Aspheterozygotes genotypes and T allele were found between healthy controls and bladder cancer, respectively(p<0.001: p=0.002). There were no significant associations between any genotypes and the stage, grade, andhistological type of bladder cancer. Our study suggested an increased risk role of NOS3 GT genotype in bladdercancer susceptibility in our Turkish population.