Objective: The aim of this study was to determine whether the presence of IL-18 polymorphisms -137 G/C and -607 A/C was associated with grade, clinical stage, and survival in patients with prostate cancer. Methods: The study cohort included 126 patients with prostate cancer. Control group consisted of 125 samples from Chinese population. Genomic DNA was extracted from EDTA-anticoagulated peripheral blood leukocytes by the salting-out method. The genotyping of the two IL-18 polymorphisms was performed using predesigned TaqMan SNP Genotyping Assays. Results: The studied IL-18 gene polymorphisms did not influence susceptibility to prostate cancer in the analyzed group of patients (IL-18-607, P = 0.342; IL-18-137 P = 0.715) but may contribute to disease onset and aggressiveness. IL-18-607 CC genotype was significantly associated with higher tumor grade (P = 0.025) and stage (P = 0.001). IL-18-137 GG genotype was correlated with higher tumor grade (P = 0.018) and stage (P = 0.007). The Cox proportional hazard model showed that tuumor grade and stage grouping were independent prognostic factors but IL-18 polymorphism was not. Polymorphism variants in the IL-18 gene (IL-18-607 and IL-18-137) may be associated with a worse prognosis for prostate cancer. Conclusion: High levels of IL-18 production may play a major role in the growth, invasion and metastasis of prostate cancer. Objective: The aim of this study was to determine whether the presence of IL-18 polymorphisms-137 G / C and -607 A / C was associated with grade, clinical stage, and survival in patients with prostate cancer. Methods: The study cohort The genotyping of the two IL-18 polymorphisms was performed using predesigned TaqMan SNPs Genotyping Assays. Results: The studied IL-18 gene polymorphisms did not affect susceptibility to prostate cancer in the analyzed group of patients (IL-18-607, P = 0.342; IL- 18-137 P = 0.715) but may contribute to disease IL-18-137 G genotype was significantly associated with higher tumor grade (P = 0.025) and stage (P = 0.001). IL-18-137 GG genotype was correlated with higher tumor grade stage (P = 0.007). The Cox proportional hazard model showed that tuumor grade and stage grouping were independent prognostic factors but IL-18 polymorphism was not. Polymorphism variants in the IL-18 gene (IL-18-607 and IL-18-137) may be associated with a worse prognosis for prostate cancer. Conclusion: High levels of IL-18 production may play a major role in the growth, invasion and metastasis of prostate cancer.