To investigate whether kinase insert domain-containing receptor (KDR) gene polymorphisms are risk factors for recurrent spontaneous abortion (RSA) in Korean women.Case-control study.University hospital.Three hundred twenty-seven idiopathic RSA patients and 230 controls with Korean ethnicity.None.The KDR -604T→C (rs2071559), 1192G→A (rs2305948), and 1719A→T (rs1870377) polymorphisms were assessed.KDR -604TC and TC+CC genotypes were more prevalent in RSA patients than in controls (adjusted odds ratio [AOR] = 2.091 and 2.076, respectively). KDR -604TC+CC/1192GG, -604TC+CC/1719AA, and -604TC+CC/1719TA+TT combined genotypes exhibited higher frequencies in RSA patients (AOR = 2.422, 2.611, and 2.216, respectively). KDR -604C/1192G/1719A, -604C/1192G/1719T, -604C/1192G, -604C/1719A, and -604C/1719T haplotype frequencies were higher in RSA patients (OR = 1.778, 2.659, 2.089, 1.678, and 1.806, respectively), whereas -604T/1192G/1719A, -604T/1192G, and -604T/1719A haplotype frequencies were lower in RSA patients (OR = 2.422, 2.611, and 2.216, respectively). No association was found between RSA and KDR 1192G→A or 1719A→T.An association between the KDR -604T→C polymorphism and RSA was found in Korean women. Carriers of the -604C variant allele were more frequent among RSA patients than among controls, suggesting that KDR -604C may confer RSA risk. The association of 1719A→T with RSA that was found in Taiwanese Han women was not observed in Korean women.