MicroRNAs (miRNAs) are short noncoding RNA molecules that plays an important role in regulating enormous number of cellular processes. Its role in the field of stem cells pertaining to stem cell differentiation and function proves to be an excellent field for research. Increased expression of oncogenic miRNAs can alter the protein products of Tumor suppressor gene while reduction or loss of tumor-suppressor miRNA may lead to elevated oncogenic proteins, thereby both of these can be employed as biomarkers or therapeutic targets in cancer management. Thus, miRNA by itself can act as biomarker and a therapeutic target in various tumors. This article aims to review the origin and role of microRNA in Stem cell differentiation and Its Pro and Anti oncogenic role in the pathogenesis of Cancer.