MircroRNAs (miRNAs) are short non-coding RNAs with a length of approximately 20-22 nucleotides, which interact with their target mRNAs at 3'-untranslated region by partial pairing. The miRNA- mRNA interaction leads to induction of mRNA degradation and eventually translational inhibition. Thus, miRNAs play an important role in virtually all cellular processes, especially differentiation, proliferation, migration, and apoptosis. The deregulation of miRNAs may lead to serious diseases including cancer. There is mounting evidence demonstrating the participation of miRNA regulation during carcinogenesis. In this review, we discuss an updated miRNA biogenesis, mechanisms involved in their deregulation, and their role in cancer development. This review also summarizes updated information on potential medicinal plants which regulate miRNA expression as a promising molecular miRNA therapeutic approach for cancers.