A microRNA (miRNA) is a small RNA consisting of approximately 22 nucleotides that plays an important role in cell growth and differentiation by regulating the expression of mRNA. miRNAs often act similarly to oncogenes and tumor suppressor genes, and dysregulation of miRNA has been examined in endometrial cancer. Studies of miRNA expression in endometrial cancer cells have shown that many miRNAs, including miR-200c, are expressed abnormally at an early stage in carcinogenesis and cause dysregulation of estrogen receptors and FOXO1. In particular, abnormal miRNA expression has been detected in various cancers and the target genes have been identified. These results indicate that miRNAs can act in a manner equivalent to oncogenes or tumor suppressors. Several studies have shown that migration and invasion of cancer cells can be inhibited by controlling these miRNAs, which suggests a possible therapeutic application. Further studies of miRNAs in endometrial cancer are required for establishment of clinical applications of miRNAs as biomarkers and treatment targets.