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© Korean Medical Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons. org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Psoriasis is a chronic inflammatory disease. Medical therapy is the mainstay of the management of psoriasis, and the main target of psoriasis treatment is immunological dysregulation. Cyclosporine and methotrexate, the main conventional psoriasis treatments, usually lead to a Psoriasis Area and Severity Index (PASI) 75 response in 50% to 60% of patients, but show some organ toxicity. Biologics for psoriasis have recently become the main therapeutic agents for moderate to severe psoriasis unresponsive to conventional treatment. Tumor necrosis factor-α inhibitors were the first anti-psoriatic biologics to be developed, and also show good efficacy for psoriatic arthritis. Ustekinumab, the sole biologic designed for the inhibition of interleukin (IL)-12/23, has been most widely used for psoriasis in Korea. The main strength of ustekinumab is its relatively long treatment interval. IL-17 inhibitors have recently been introduced in Korea for psoriasis treatment. Secukinumab and ixekizumab are currently available IL17 inhibitors that block the development of psoriasis lesions in the downstream events of psoriasis pathogenesis. They have excellent therapeutic efficacy, with a PASI 90 response in up to 60%-70% of patients. Selective IL-23 inhibitors have been more recently introduced in our country. They have an excellent PASI 90 response, and a longer injection interval than IL-17 inhibitors. New immunological modulators such as phosphodiesterase inhibitors, tyrosine kinase 2 inhibitors, and janus kinase inhibitors are planned to be introduced for psoriasis treatment. These are small molecules that can be administered orally, and some patients who are reluctant to receive injection therapy are expected to favor these therapeutic agents.