Background/aim: IL-23R gene polymorphisms and the association of these polymorphisms with serum IL-23 levels were investigated in patients with psoriasis in the current study. Materials and methods: Sixty-seven patients with psoriasis who were admitted to our dermatology outpatient clinic and 67 healthy controls were included in the study. Polymorphisms of the IL-23R gene were determined by KASP-PCR method, and serum IL-23 levels were determined by ELISA method.Results: The distribution of IL-23R gene polymorphisms rs2201841, rs11209026, rs7530511, rs1343152, and rs11465804 was not significantly different in the patient and control groups. The AA genotype of the rs2201841 locus in males and the GA genotype in females, as well as the AA genotype of the rs1343152 locus in males and the CA genotype in females, were statistically significant in patients with psoriasis. The mean serum IL-23 level was significantly lower in the patient group (42.62 ± 5.96) compared to the control groups (75.76 ± 13.24). Conclusion: IL-23R gene polymorphisms including rs2201841, rs11209026, rs7530511, rs11465804, and rs1343152 were not found to be significantly related to psoriasis. Different genetic polymorphisms may play a role in the development of psoriasis in female and male populations. Ethnic differences between different populations may have led to differences in the distribution of polymorphisms in the current study with compared to other published studies. Additionally, many different genes, polymorphisms, and environmental factors that have an effect on the development of psoriasis may affect the disease process.