Background/aim: The purpose of the present study was to investigate whether endothelial nitric oxide synthase (eNOS) gene polymorphisms play a role in prostate cancer (PCa). Materials and methods: We examined three eNOS gene polymorphisms (T-786C promoter region, G894T, and Intron 4 VNTR 4a/b) at extracted DNAs from 50 formalin-fixed paraffin-embedded tissues of PCa patients. For the controls, blood samples obtained from 50 healthy men were studied. Genotyping of molecular variants was performed by PCR-RFLP technique. Results: We found that the TC genotype of the T-786C polymorphism was associated with PCa risk (OR: 3.325, CI: 1.350-8.188, P = 0.008). The eNOS G894T polymorphism was also associated with PCa. The frequency of the 894T allele was significantly higher in PCa patients. No association was identified between intron 4 VNTR polymorphism and PCa. Conclusion: We found significant differences in genotypic and allelic frequencies between PCa patients and controls for eNOS T-786C and G894T polymorphisms. The presence of the T-786C genotype and 894T allele in carriers increased the risk of PCa. No association was found between intron 4 VNTR polymorphism and PCa patients.