Introduction: Prostate cancer is the most common non-cutaneous male cancers, contributing to significant mortality rates globally. Mutations of RNase L, an enzyme involved in inflammatory and immunological pathways, have been speculated to predispose to cancer. This study assesses three different mutations of the RNase L gene in Irish prostate cancer patients, including one linked with general cancer susceptibility never investigated before in prostate cancer (rs3738579), and reports on links with aggressive cancer. Methods: 134 patients had their RNase L mutation status determined by polymerase chain reaction (PCR) of serum DNA. Complementary clinical details for each patient are statistically analysed. Results: No link to age of diagnosis, high grade disease or prostate specific antigen (PSA) level at diagnosis was demonstrated with any of the studied single nucleotide polymorphisms (SNP). The SNP variation was consistent with that of published international series. Conclusion: SNP genotypic frequencies in Ireland are consistent with international findings. The studied RNase L mutations including rs3738579 do not appear to have a significant impact on our patient population.