Myxovirus resistance A (MxA) is an antiviral protein induced by type I interferons α and β (IFN-α and IFN-β) that can inhibit virus replication. We examined whether the MxA polymorphisms were related to the risk and severity of enterovirus 71 (EV71) infection in Chinese populations. The MxA C-123A and G-88T polymorphisms were genotyped in two independent case-control populations in China by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analysis. Multivariate logistic regression analysis was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs). MxA messenger RNA was quantified by real-time quantitative PCR in peripheral blood mononuclear cells (PBMCs) from 45 healthy children and 19 patients with EV71 infection. Significantly decreased susceptibility to EV71 infection was observed for the -123A allele and -88T allele carriers, with ORs (95% CIs) estimated as 0.56 (0.39-0.81) and 0.64 (0.47-0.88), respectively, in the northern population. This association was confirmed in the southern population, with ORs (95% CIs) estimated as 0.58 (0.38-0.89) and 0.67(0.47-0.95), respectively. The A- 123T- 88 haplotype was also significantly associated with lower risk of EV71 infection in both the northern (OR = 0.62; 95% CI = 0.44-0.85) and the southern population (OR = 0.63; 95% CI = 0.43-0.92). Furthermore, we observed higher MxA messenger RNA levels in IFNβ1a-stimulated PBMCs from the -123A or -88T allele carriers compared with that from nocarriers. Our findings suggest that polymorphisms in the MxA promoter may play a role in mediating the susceptibility to EV71 infection in Chinese population.