Prostate cancer (PCa) is the most common type of neoplasm in European males. Genetic and epigenetic factors contribute to PCa development and progression. In this study, we aimed to assess the relationship between PCa and polymorphisms in the genes encoding endothelial nitric oxide synthase (eNOS), catalase (CAT), and myeloperoxidase (MPO). In total, 193 patients were included in the study. Patients were divided into three groups: PCa (78), benign prostate hyperplasia (40), and control males (75). The parameters assessed included body mass index (BMI), smoking habits, presence of prostatism, prostate-specific antigen (PSA) levels, Gleason scores of prostate specimens, as well as polymorphisms in eNOS-G894T, CAT-262T, and MPO G-463T genes. BMI and smoking status of controls and patient groups showed no significant difference. CAT-262T gene polymorphism was found to be homozygous in 35.4% of PCa patients, which was 4.02-fold that in the controls (P = 0.006). There was no statistically significant difference in eNOS-G894T and MPO G-463T gene polymorphisms between any of the groups. In conclusion, we found catalase levels to be associated with PCa diagnosis and PSA value. We did not find any significant differences between groups for other polymorphisms, but we believe that further studies with a large sample size may be needed before drawing definite conclusions.