Genetic susceptibility plays a major role in the etiology of Graves' disease (GD). A recent study revealed that the A946T polymorphism (rs1990760) in interferon induced helicase (IFIH1) gene was a susceptible locus for GD. A case-control study in a Chinese population was undertaken, with 261 GD patients and 206 healthy subjects, to analyze the association of A946T polymorphism in IFIH1 gene with GD. In addition, the distribution of IFIH1 genotypes was investigated in subgroups according to the onset age and the Graves' ophthalmopathy (GO). No significant differences in the allele and genotype frequencies for A946T polymorphism were found between GD patients and healthy controls (chi2 = 2.834, P = 0.242; chi2 = 1.127, P = 0.288). The genotype-phenotype correlation was not identified either. Therefore we were unable to find the association of A946T polymorphism of the IFIH1 gene with the development of GD in a Chinese population.