Abstract: Objective To explore the relationship between methionine synthase reductase(MTRR) and 5, 10-methy-lenetetrahydrofolate dehydrogenase(MTHFD1L) gene polymorphism and microtia.Methods Totally 180 microtia cases and 141 age-matched healthy physical examinees were recruited at 3 hospitals in Jiangsu province between 2012-2014.The genotypes of MTRR and MTHFD1L of the participants were examined with multiple PCR and multiple ligase detection reaction(LDR).Frequencies and allele distribution of MTRR and MTHFD1L gene between cases and controls were compared with Chi-square test.Results The genotype ratios of MTRR rs1801394 were 54% for AA, 42% for AG, and 4% for GG in the cases and 48% for AA, 44% for AG, and 9% for GG in the controls, without statistically significant difference between the two groups(P>0.05).The genotype ratios of MTHFD1L rs1950902 were 6% for TT, 40% for CT, and 54% for CC in the cases and 9% for TT, 43% for CT, and 48% for CC in the controls, without statistically significant difference between the two groups(P>0.05).No significant gender-difference in the genotype distribution of MTRR rs1801394 and MTHFD1L rs1950902 was observed(P>0.05).The allele distribution of MTRR rs1801394 and MTHFD1L rs1950902 were not significantly different between the cases and the controls(P>0.05).Conclusion The single nucleotide polymorphism of MTRR and MTHFD1L genes may not be correlated to genetic susceptibility of microtia.