MicroRNAs (miRNAs) are small, noncoding RNAs of 18-25 nucleotides that are generally believed to either block the translation or induce the degradation of target mRNA. miRNAs have been shown to play fundamental roles in diverse biological and pathological processes, including cell proliferation, differentiation, apoptosis and carcinogenesis. Fibrosis results from an imbalance in the turnover of extracellular matrix molecules and is a highly debilitating process that can eventually lead to organ dysfunction. A growing body of evidence suggests that miRNAs participate in the fibrotic process in a number of organs including the heart, kidney, liver and lung. In this review, we summarize our current understanding of the role of miRNAs in the development of tissue fibrosis and their potential as novel drug targets.