Objective To explore the association between the genetic polymorphism of CYP3A4,CYP2D6 and response to methadone maintenance treatment(MMT)among heroin-dependent patients.Methods Patients undergoing MMT in 6 MMT clinics were randomly selected,information about general socia-demographic characteristics,drug abuse history,and MMT data of patients were collected,genotypes of peripheral blood CYP3A4 and CYP2D6 polymorphic loci were detected.Results A total of 820 patients were enrolled in the study,210 cases were with good response and 610 cases with poor response to MMT.Difference in age between different response groups was statistically significant(P<0.05).Distribution of genotype frequency and allele frequency of CYP3A4 rs2242480 and CYP2D6 rs16947 between good response and poor response groups was not significantly different(both P>0.05).Conclusion The association between CYP3A4 rs2242480,CYP2D6 rs16947 and response to MMT has not yet found in heroin-dependent patients.