PURPOSE: Preeclampsia is a multisystem human pregnancy-specific disorder. The pathophysiology of preeclampsia is linked with over-stimulation of inflammatory cytokines by placental ischemia via reduced uterine perfusion pressure during pregnancy. Although an increase in tumor necrosis factor (TNF)-alpha has been reported in preeclamptic women, there is little evidence of a relationship between TNF-alpha gene variations and preeclampsia. In this study, we identified a single-nucleotide polymorphism (SNP), C-850T, in the TNF-alpha gene promoter region in Korean preeclamptic women and investigated the association between this SNP and the development of preeclampsia. MATERIALS AND METHODS: This polymorphism was analyzed in peripheral blood samples from 198 preeclamptic pregnancies and 194 normotensive pregnancies using a SNapShot kit and an ABI Prism 3100 Genetic analyzer. RESULTS: Genotypes and allele frequencies for C-850T did not differ between preeclamptic and normotensive pregnancies. The distributions of genotypes (CC, CT and TT) were 74.3%, 22.2% and 3.5%, respectively, in preeclamptic pregnancies, and 71.6%, 25.8% and 2.6%, respectively, in normotensive pregnancies. The frequencies of the C and T alleles were 0.85 and 0.15 in preeclamptic pregnancies and 0.84 and 0.16 in normotensive pregnancies, respectively. There was no increased risk of preeclampsia in subjects with the CT (OR, 0.83; P=0.44) or TT genotypes (OR, 1.32; P=0.64). CONCLUSION: We found no differences in the genotypes or allele frequencies of the TNF-alpha gene polymorphism between preeclamptic and normotensive pregnancies. This study suggests that the TNF-alpha gene polymorphism may be not associated with the development of preeclampsia in pregnant Korean women.