In the last few years, the presence of single nucleotide polymorphisms (SNPs) has been investigated in many tumors as predictor of disease aggressiveness and clinical outcome. We searched for relevant articles from 1998 to 2015 about the impact of SNPs in prostate cancer. Particularly, in this article, we review the pathogenetic, prognostic and predictive significance of gene polymorphisms in prostate tumor, providing a brief overview of studies in which the possible role of genetic variants was investigated in clinical settings. Because conflicting results often emerge about the impact of gene polymorphisms in prostate cancer, further larger studies are warranted in order to introduce gene polymorphism into clinical practice as biomarkers.