Abstract Background Prostate cancer (PCa) is an androgen-dependent disease. Nonetheless, the role of single nucleotide polymorphisms (SNPs) in genes encoding androgen metabolism remains an unexplored area. Purpose To investigate the role of germline variations in cytochrome P450 17A1 ( CYP17A1 ) and steroid-5α-reductase, α-polypeptides 1 and 2 ( SRD5A1 and SRD5A2 ) genes in PCa. Patients and methods In total, 494 consecutive Spanish patients diagnosed with nonmetastatic localized PCa were included in this multicenter study and were genotyped for 32 SNPs in SRD5A1, SRD5A2, and CYP17A1 genes using a Biotrove OpenArray NT Cycler. Clinical data were available. Genotypic and allelic frequencies, as well as haplotype analyses, were determined using the web-based environment SNPator. All additional statistical analyses comparing clinical data and SNPs were performed using PASW Statistics 15. Results The call rate obtained (determined as the percentage of successful determinations) was 97.3% of detection. A total of 2 SNPs in SRD5A1 —rs3822430 and rs1691053—were associated with prostate-specific antigen level at diagnosis. Moreover, G carriers for both SNPs were at higher risk of presenting initial prostate-specific antigen levels>20 ng/ml (Exp( B ) = 2.812, 95% CI: 1.397–5.657, P = 0.004) than those who are AA-AA carriers. Haplotype analyses showed that patients with PCa nonhomozygous for the haplotype GCTTGTAGTA were at an elevated risk of presenting bigger clinical tumor size (Exp( B ) = 3.823, 95% CI: 1.280–11.416, P = 0.016), and higher Gleason score (Exp( B ) = 2.808, 95% CI: 1.134–6.953, P = 0.026). Conclusions SNPs in SRD5A1 seem to affect the clinical characteristics of Spanish patients with PCa.