Purpose: To evaluate thiol/disulfide homeostasis in both maternal and fetal compartment in the presence of fetal growth restriction (FGR). Materials and methods: A prospective case-control study was carried out in women with FGR (n: 40) or normally growing fetus (n: 40). FGR was defined as estimated fetal weight below the 10th percentile for the gestational age. Maternal serum and fetal cord blood samples were collected from all participants and native thiol-disulfide exchanges were examined with automated method enabling the measurement of both sides of thiol-disulfide balance. Results: Native thiol, total thiol and disulfide amounts were decreased in the maternal serum and fetal cord blood of babies born to women with FGR (p < .05). The most sensitive marker was maternal native thiol (82.5, 95% confidence interval, 67.22-92.66%), while the maternal total thiol had highest specificity value (77.5, 95% confidence interval, 61.55-89.16%). Conclusions: Maternal and fetal serum thiol/disulfide profiles may use prediction of FGR severity and its neonatal outcome.