Rheumatoid arthritis is a chronic inflammatory disease that causes deformed joints and leads to gradually reduced mobility. The field of rheumatic diseases is one of the fastest developing medical disciplines. All the rheumatic diseases share an abnormal immune response to the antigens. Although rheumatoid arthritis is not a new disease, it is only in the last decade that we are facing positive changes in its medical treatment due to development of biological drugs. Better understanding of pathogenesis of the disease opened the doors for more efficient development of medication for treatment autoimmune diseases. Biological medications target and block the activity of immune competent cells and their products - cytokins and play a big role in clinical treatment of severe forms of rheumatoid arthritis. In rheumatology, we use mainly inhibitors of TNF-α and interleukins 6, inhibitors of CD20+ B cells and T-cell activation inhibitors. The objective of my thesis is to research and introduce the key information about the mechanism of action of biological medications that are currently being used.