Mi RNAs are endogenous, non-coding, single-stranded RNAs with about 21 nucleotides in length. They are known as post-transcriptional regulators by binding to 3′-untranslated region of their target genes. Recently, it has been shown that miRNA was associated with the pathogenesis of rheumatoid arthritis(RA) in various aspects, such as chronic inflammation and hyperplasia in the synovial lining cells. The purposes of this review are to provide an overview on our current understanding of miRNA expression and f...