OBJECTIVE We sought to determine whether the Fas (-670) single-nucleotide polymorphism is associated with intrauterine growth restriction. STUDY DESIGN Twenty-seven pregnant women with intrauterine growth restriction in the absence of preeclampsia and 50 pregnant women with uncomplicated pregnancies were studied. DNA was extracted from maternal and infant buccal smears and allelic discrimination was performed for Fas (-670). Student t test, chi2, and z tests were used. RESULTS There were no differences in maternal age, race, or parity between the intrauterine growth restriction and control patients. Mothers of intrauterine growth restriction infants had a significantly different genotype distribution for this single nucleotide polymorphism, and for the ratio of GG genotype (GG, AA: 0.41, 0.18 maternal intrauterine growth restriction; 0.14, 0.32 controls; respectively, P=.03). These genotype differences were significantly different in white, but not black mothers with intrauterine growth restriction (P=.03, and .3; respectively). In contrast, no differences were found in infants' Fas (-670) single-nucleotide polymorphism genotypes. CONCLUSION This study demonstrates an association between the maternal Fas (-670) single-nucleotide polymorphism and the development of intrauterine growth restriction.