Backgroud: PIWI-interacting RNAs (piRNAs) are a kind of small non-coding RNAs which interact with PIWI proteins and play a vital role in safeguarding genome. Single nucleotide polymorphisms (SNPs) are widely distributed variations which are associated with diseases and have rich information. Up to now, various studies have proved that SNPs on piRNA were related to diseases. Objective: In order to create a comprehensive source about piRNA-related SNPs, we developed a publicly available online database piRSNP. Methods: We systematically identified SNPs on human and mouse piRNAs. piRSNP contains 42,967,522 SNPs on 10,773,081 human piRNAs and 29,262,185 SNPs on 16,957,706 mouse piRNAs. Results: 7,446 SNPs on 519 cancer-related piRNAs and their flanks are investigated. Impacts of 2,512 variations of cancer-related piRNAs on piRNA-mRNA interactions are analyzed. Conclusion: All these useful data and piRNA expression profiles of 12 cancer types in both tumor and pericarcinomatous tissues are compiled into piRSNP. piRSNP characterizes human and mouse piRNArelated SNPs comprehensively and could be beneficial for researchers to investigate subsequent piRNA functions. Database URL is http://www.ibiomedical.net/piRSNP/.