Stem cells and miRNAs are two of the most intriguing research topics in recent years. Stem cells with properties of self-renewal and multipotency are remarkable cells since they play key roles in animal development and tumorigenesis. microRNAs (miRNAs) are ~22nt non-coding RNAs, which have spatiotemporally specific ex-pression patterns, and are highly conserved between species. Researchers have demonstrated that miRNAs can regulate gene expression at post-transcriptional level, and their action is one of the essential intracellular regula-tory pathways. Recent evidence showed that miRNAs can regulate stem cells self-renewal and differentiation. The evidence mostly derived from the following research strategies: (1) deletion or mutation of the genes that encoding essential enzymes for miRNAs biogenesis, such as Dicer1, Loqs, DGCR8, and Argonaute; (2) screening of specific miRNAs from stem cells and investigation of their function. Comprehension of the miRNAs functions in stem cells is of great importance for further understanding their self-renewal and differentiation mechanism, as well as identification of stem cells. This paper reviews the potential roles of miRNAs in stem cellson the basis of recent researches.