MicroRNAs (miRNAs) are well established as global gene regulators and thus, slight alterations in miRNA levels as well as their ability to regulate their targets may cause important cellular changes leading to cancer risk. 3´ untranslated region (UTR) miRNA binding site single nucleotide polymorphisms (SNPs) have added another layer of possible genetic variation involved in the complex process of oncogenesis. Identifying these key genetically inherited effectors of miRNA functioning has improved our understanding of the complexity of disease. Interest in the field has grown rapidly in only the last 5 years, with several studies reporting on the role of 3´UTR binding site SNPs as genetic markers of increased cancer susceptibility, as well as biomarkers of cancer type, outcome and response to therapy. Currently, there are numerous known miRNA binding site SNPs associated with multiple cancer subtypes.