Interleukin 23 receptor (IL-23R) plays a role in the pathogenesis of multiple autoimmune processes. The relationship between allograft outcomes and the IL-23Rvariant genotypes has not been reported on previously. Therefore, we examined the relationship between this genetic polymorphism and kidney transplant outcomes.This is an observational cohort study and 422 renal transplant recipients (RTRs) were enrolled. Polymerase chain reaction-restriction fragment length polymorphism was used for the measurement of IL-23R genetic polymorphisms. We used a composite end-point incorporating serum creatinine (SCr) doubling, graft failure and death as the primary outcome. Secondary outcomes included biopsy-proven acute rejection (BPAR), biopsy-proven interstitial fibrosis/tubular atrophy (IF/TA) and individual primary outcome. The risks of developing primary and secondary outcomes were compared between the different IL-23R genotypes and alleles.With a mean follow-up of 79.3±28.8 months, 26 patients in the IL-23R genotype AA group and 32 patients in the IL-23R genotype AC/CC group reached the primary outcome (p=0.061). RTRs who carried the IL-23R AC/CC genotype (aHR 1.78; 95% CI. 1.01-3.12; p=0.046) and C allele (aHR 1.48; 95% CI. 0.96-2.28; p=0.075) had a higher risk of developing primary outcome as compared to those with IL-23R AA genotype and A allele, respectively. Moreover, RTRs who carried the IL-23R AC/CC genotype and C allele had a higher risk of developing biopsy-proven IF/TA (p=0.012; p=0.012) and SCr doubling (p=0.024; p=0.042) as compared to those with IL-23R AA genotype and A allele, respectively. The risk of BPAR, graft failure and death between the IL-23R genotypes and alleles were comparable.IL-23R polymorphism may have a potential immuno-modulating role in long-term allograft outcome.