Rheumatoid arthritis is a chronic, systemic, inflammatory autoimmune disease that symmetrically affects large and small joints and usually occurs between the ages of thirty and fifty, affecting 0.5-2% of the world's population, more often women. The main tissues affected by inflammation are the synovial membrane of the joints and the tendon. The cause of the disease is not fully clarified, but the disease is characterized by complex pathogenesis that involves the interaction of genetic, immune and environmental factors. The disease is also accompanied by numerous comorbidities, such as nodules in the area of the elbows and joints of the fingers, pulmonary, cardiovascular and hematological disorders, and secondary Sjögren's syndrome. Early diagnosis is important to prevent progression of the disease and to accomplish earlier remission. Diagnosis is still not distinctive and in the early stages of the disease it is very difficult to determine whether is it exactly rheumatoid arthritis considering certain similarities with other autoimmune diseases or other types of arthritis. Diagnosis involves the number of injured joints, duration of inflammation, radiographic images and laboratory findings (presence of RF and / or ACPA in serum, increased CRP and erythrocyte sedimentation). Treatment is usually started with DMARDs (disease-modifying anti-rheumatic drugs), mainly methotrexate, except in the case of existing contraindications or poor tolerability, with occasional use of corticosteroids and NSAIDs. If no satisfactory therapeutic response is achieved another DMARD or biological drug is added in the therapeutic regimen. Biologic agents for use in therapy of RA include TNF-α inhibitors, IL-1 antagonists, T-cell activation inhibitors, B-cell antagonists and IL-6 antagonists. Their most common side effects include severe infections, injection site reaction, gastrointestinal side effects and bone marrow suppression. Mutual combination of biological drugs is not recommended.