Abstract: Objective:To explore the correlation of the polymorphism of cytotoxic T lymphocyte associated antigen-4(CTLA-4) gene and recurrence of Graves' disease(GD).Methods:The A/G polymorphisms of CTLA-4 gene exon seventeenth codon 49 locus in 102 patients with GD recurrence, who included 60 recurrence cases within 3 years of withdrawal drug(A group) and 42 recurrence cases after 3 years of withdrawal drug(B group), 40 primary GD patients(primary group) and 80 healthy people(normal control group) were detected using polymerase chain reaction restriction fragment length polymorphism.Results:The frequency distribution of genotype and allele in CTLA-4 gene exon 1 of 49 locus showed that the frequency of GG genotype and G allele in primary GD patients were higher than those in normal control group(P<0.01), the frequency of GG genotype in A group was higher than that in B group and primary group(P<0.01), and the frequency of GG genotype in B group was higher than that in primary group(P<0.01).Conclusions:The A/G polymorphism of CTLA-4 gene exon seventeenth codon 49 locus is related to the GD occurrence, the GG genotype of which may be the reason of the poor effect of antithyroid drugs and early recurrence in GD patients.