BACKGROUND After renal transplantation, immunosuppressants should be administered to prevent organ rejection and prolong graft survival. One of them is tacrolimus, which is metabolized by the CYP3A enzyme family. The variability of the CYP3A5 gene in renal transplant recipients has been previously studied for its correlation with acute rejection and allogeneic kidney function. CYP3A5 enzyme is also present in the renal tissue, and its relevance has not yet been extensively investigated. This study aimed to evaluate the effect of donor and recipient CYP3A5 expression status on early and long-term transplant outcomes. MATERIAL AND METHODS Single-nucleotide polymorphism in CYP3A5 (rs776746) was analyzed in 95 kidney transplant recipients and their grafts. The effect of donor and recipient genotypes on the primary endpoint, which was the loss of the renal graft over 5-year follow-up, was assessed. The secondary endpoints were biopsy-proven acute rejection, proteinuria, delayed graft function, and renal function. RESULTS Patients who received a CYP3A5*1 allele-carrying kidney (n=16) were at greater risk of graft loss (adjusted hazard ratio, 95% CI: 10.61, 2.28-49.42, P=.003) than those with the CYP3A5*3/*3 genotype (n=79). Renal CYP3A5 expression was also a predictor of acute rejection between the 2nd and 12th post-transplant months (adjusted odds ratio, 95% CI: 4.36; 1.08-17.6, P=.038) and proteinuria at different time intervals. No effect of the recipient CYP3A5 genotype was observed. CONCLUSIONS The donor CYP3A5 genotype is associated with inferior transplantation outcomes. Local renal tacrolimus metabolism is a potential target for improving long-term transplantation outcomes.