Abstract: In this study, IRF3 gene was chosen as a candidate gene for evaluating its effect on porcine immune traits. A SNP (HQ026024: g.4252T>C) in exon7 of IRF3 gene was demonstrated by PCR-SSCP analysis and sequencing. Immune traits including IFN-γ and IL10 concentrations in serum were measured when the pigs are at 20th day of age. The further association analysis of SNP genotypes with immune traits were also conducted in 3 pig breeds including Large white, Landraces and Chinese indigenous breed Dingyuan black pig. The results indicated that the SNP of IRF3 gene had highly significant effects on level of IFN-γ and IL10 (day 20) in serum (p = 0.0344; p = 0.0121) and ratio of IFN-γ to IL10 (day 20) in serum (p = 0.0315). The results suggested that the IRF3 gene could be regarded as a molecular marker gene for genetic selection of these immune traits in the pig breeding program.