Acquired aplastic anemia (AA) is a rare disease with a complex pathogenesis. In most cases, T cell-mediated immune destruction of hematopoietic cells results in peripheral blood pancytopenia and bone marrow hypoplasia. A subset of the heterodimeric interleukin-23 receptor gene (IL-23R) is significantly associated with autoimmune-mediated diseases. To examine whether IL-23R single nucleotide polymorphisms (SNPs) might contribute to AA, we selected three IL-23R SNPs with amino acid changes (rs11209026: p.Arg381Gln; rs41313262: p.Val362Ile; and rs11465797: p.Thr175Asn) and compared their frequencies in 279 AA patients and 184 ethnically matched healthy controls. The three SNP prevalences were similar between the AA patients and controls. The Arg381Gln variant, which has a strong protective effect against inflammatory bowel disease, showed no association with AA. Furthermore, IL-23 levels in sera were measured in the AA patients and in controls, and there were no significant differences among them. Our results indicate that these three IL-23R SNPs and serum IL-23 level have no apparent impact on susceptibility to AA.