Epigenetics is a steadily growing research area. In many human diseases, especially in cancers, but also in autoimmune diseases, epigenetic aberrations have been found. Rheumatoid arthritis is an autoimmune disease characterized by chronic inflammation and destruction of synovial joints. Even though the etiology is not yet fully understood, rheumatoid arthritis is generally considered to be caused by a combination of genetic predisposition, deregulated immunomodulation, and environmental influences. To gain a better understanding of this disease, researchers have become interested in studying epigenetic changes in rheumatoid arthritis. Here, we want to review the current knowledge on epigenetics in rheumatoid arthritis.