Rheumatoid arthritis (RA) is a systemic, autoimmune disease, which is characterized by inflammation and progressive destruction of the synovial joints leading to pain, long term disability, and reduced quality of life in many patients. Human genetic and epidemiology studies have shown that causal factors of disease include pre-determined contributions from at least 40 different genes and the effect of environmental factors. Epigenetic represent a new aspect in autoimmunity, which refers to changes in gene expression that do not involve changes in DNA sequence. Recently, the list of molecules important for RA pathogenesis has been extended by microRNAs (miRNAs), which play a key role in regulating both adaptive and innate immune response, development and differentiation of immune cells, and the prevention of autoimmunity.