MicroRNAs (miRNAs) are endogenous non-coding small RNAs of approximately 22 nucleotides in length. miRNAs repress expression of target genes at the posttranscription level. Biological relevance of miRNAs have been investigated in physiological and pathological conditions, revealing their involvement in fine tuning of the biological events, such as cell proliferation, differentiation and cell death. In 2008, miR-146a and miR-155 were reported to be involved in the pathology of rheumatoid arthritis. Subsequently, expression and function of other miRNAs in rheumatoid arthritis have been reported. These reports suggest that miRNAs could be novel candidates for the therapeutic target or biomarker of rheumatoid arthritis. Further investigations are required to identify, characterize and modulate the key miRNA in the pathology of rheumatoid arthritis.