Abstract: OBJECTIVE To investigate the distribution of CYP3A5*3 in Chinese population, and clarify its correlation with blood drug level and clinical efficacy of tacrolimus. METHODS Two hundred and sixty-eight tacrolimus steady state minimal concentration samples were collected from 55 patients with chronic glomerulonephritis. The blood drug level of tacrolimus was measured by enzyme multiplied immunoassay technique. The genotypes of CYP3A5*3 were determined by TL998A fluorescence detector. The association between different CYP3A5*3 genotypes and the blood drug level and clinical efficacy of tacrolimus were analyzed. RESULTS In 268 parts of tacrolimus steady state minimal concentration, the curative effect of 5-< 10 ng·mL^-1(82.0%) and 10-20 ng·mL^-1(82.6%) were significantly higher than that of <5 ng·mL^-1(P<0.05). And the clinical efficiency of tacrolimus in the range of 5-<10 ng·mL^-1 and 10-20 ng·mL^-1 were similar. Use the pairwise comparison methods to compare steady state minimal concentration, daily dose, minimal concentration/daily dose(C/D) showed that the steady state minimal concentration of tacrolimus with GA and GG genotype patients were significantly increased than that of AA genotypes, and GA genotype recipients were higher than that of GG genotypes(P<0.05). Tacrolimus dose of GG genotype patients were significantly lower than those of GA and AA genotypes, and GA genotype patients were lower than that of AA genotypes (P<0.05). C/D value of GG genotype patients were significantly higher than those of GA and AA genotypes, and GA genotype recipients were higher than that of AA genotypes(P<0.05). However, the clinical efficacy of tacrolimus with mutant type and wild type of CYP3A5*3 were similar. CONCLUSION CYP3A5*3 genetic polymorphism significantly influences tacrolimus concentration in Chinese chronic glomerulonephritis patients, and G allele carriers have higher C/D values and need smaller tacrolimus daily dose. CYP3A5*3 genetic polymorphism may be not associated with clinical efficacy.