The aim of this study was to investigate IL-23R gene polymorphisms (rs2201841, rs11209026, rs7530511, rs11465804, rs1343152) and the relationship of these polymorphisms with serum IL-23 levels and clinical features of Turkish patients with psoriasis (age at onset, duration and severity of disease, family history, and nail and joint involvement). The gene discussed is IL23R; the disease is psoriasis.