OBJECTlVE To investigate the association between CYP3A5 genotypes and the early efficacy of tacrolimus ( Tac) and cyclosporin A ( CsA) in renal transplantation recipients, and provide a basis for individualized treatment. METHODS Seventy-four kidney transplantation recipients were en-rolled in this study between August 2012 and April 2013. Thirty-one patients were treated with the combi-nation of CsA, MMF and methylprednisolone while the rest were treated with Tac, MMF and methylpred-nisolone. The genotype CYP3A5 was detected by sequence specific primer-polymerase chain reaction ( SSP-PCR) before transplantation. The levels of Tac and CsA were detected by ELlSA and chemilumi-nescence, respectively, to monitor the blood concentration/dose of drugs ( c/D) at 2 weeks, 1 month, 2 months, 3 months and 6 months after transplantation. Simultaneously, the concentrations of blood glu-cose, creatinine, urea nitrogen and uric acid were determined with hexokinase method, creatininase method, urease method and uricolase method, respectively. RESULTS Among the 74 recipients, 9.5%carried CYP3A5?1/?1, 48.6%carried CYP3A5?1/?3 and 41.9%carried CYP3A5?3/?3. According to the phenotype of CYP3A5, the patients were divided into CYP3A5 expression group ( including CYP3A5?1/?1 and CYP3A5?1/?3) and non-expression group ( including CYP3A5?3/?3) , which accounted for 58.1%and 41.9%of the cases, respectively. Among the patients taking Tac, the median value of c/D at 2 weeks, 1 month, 2 months, 3 months and 6 months was 25.49, 49.64, 53.72, 51.9 and 44.5 in CYP3A5 expression group, and 65.48,100.84,99.54,123.01 and 133.21 in non-expression group. The c/D ratio of CYP3A5 non-expressers was higher than among CYP3A5 expressers at each time point ( P<0.05) . The initial dose of Tac 0.1 mg·kg-1 was high for CYP3A5 non-expressers, and the kidney function recovered more slowly than among CYP3A5 expressers and kidney damage occurred. However, there was no association between CYP3A5 genotype and the early efficacy of CsA. The levels of blood glucose, creatinine, urea nitrogen and uric acid were not significantly different between CYP3A5 expression and non-expression groups. CONCLUSlON CYP3A5 non-expression recipients whose starting amount of Tac was 0.1 mg·kg-1 have drug overdoses. CYP3A5 genotype is one of the factors affecting the efficacy of Tac. CYP3A5 genotype has no association with the efficacy of CsA in renal transplantation recipients.