In recent years, treatment of rheumatoid arthritis (RA) with biological agents, also called biological disease-modifying antirheumatic drugs (bDMARDs), has become standard. bDMARDs are generally used for patients with an inadequate response to methotrexate and/or other conventional DMARDs. Thus far, tumor necrosis factor (TNF) inhibitors, an interleukin 6 inhibitor and a T cell-selective regulatory bDMARD have been approved for RA in Japan. The strategy of RA management has also changed. Clinical remission is recommended as a primary goal of treatment because this may prevent subsequent articular destruction and impairment of joint functions. TNF inhibitors are also prescribed to patients with other inflammatory rheumatic diseases, such as ankylosing spondylitis, psoriatic arthritis and Behcetʼs disease, whose conditions have not adequately responded to conventional therapy. Furthermore, B cell depletion therapy with an anti-CD20 monoclonal antibody is an important option in the treatment of refractory anti-neutrophil cytoplasmic antibody-associated vasculitis, especially in granulomatosis with polyangiitis. In addition, biological agents have also been used for off-label indications. However, these agents are costly and may cause serious infections. This article reviews the current use of biological agents in adult rheumatic diseases.