Abstract: 　Objective　To explore the association of T cell immunoglobulin- and mucin-domain-containing molecule-3 (TIM-3) gene polymorphism and IFN-γ levels with the incidence of primary nephrotic syndrome (PNS) in children. Methods           A case-control study was conducted and 21 Han patients with PNS were selected and included in case group. Meanwhile, 20 each from Mongolian and Han were selected and assigned into control group and at least three generations of their family members were from the same nationality. PCR-restriction fragment polymorphism analysis was used to detect and analyze single nucleotide polymorphisms of exon －574A/C in TIM-3 gene in PNS children and controls. Also the genotype and allele frequencies between the two groups were compared. Enzyme linked immunosorbent assay (ELISA) was used to detect the level of serum IFN-γ and its changes was analyzed. Results　There was no significant difference in the distribution of genotypes (AA, AC, CC) of exon －574A/C in TIM-3 gene between the Han and Mongolian subgroups in control group (P=0.741). Neither did the allele frequency between the two groups (P=0.655). Compared with control group (Han and Mongolian), the frequencies of AA, AC and CC genotypes were 9.52%, 28.57% and 61.90% respectively in －574A/C loci of the Han nationality children with PNS. There was significant difference in genotypes distribution between the two groups (P=0.017). The frequency of C allele in PNS children of Han nationality was 76.2% which was higher than that in normal control group (50%), and the difference was statistically significant (P=0.005). Compared with A allele carriers, the risk of PNS in C allele carriers increased by 3.20  times (95%CI: 1.39~7.37). There were no significant differences in serum IFN-γ among the Han nationality with PNS, Han and Mongolian normal control groups (P>0.05). Conclusion　The single nucleotide polymorphism of the exon －574A/C of TIM-3 gene may be related to the pathogenesis of PNS in children. In addition, IFN-γ is not associated with the incidence of primary nephrotic syndrome in children.