Objective- To assess maternal endothelial function in singleton pregnancies complicated by intrauterine growth restriction (IUGR) due to placental dysfunction. Design- Prospective cohort study. Setting- 37 pregnant women who underwent endothelial function assessment using EndoPATTM device. Population or Sample- Study population included two groups: 1. Pregnancies with estimated fetal weight below 10th percentile and abnormal umbilical artery flow (n=15); 2. Pregnancies with normal fetal growth without placental complications matched by gestational age (n=22). Exclusion criteria included diseases with potential vascular dysfunction or smoking. Methods- EndoPAT device evaluates changes in peripheral vascular flow and tone in reaction to temporal ischemia. Normal post-ischemic endothelial reaction is an increase in vascular flow. A ratio of the readings before and after ischemia is used to calculate the score for endothelial function, called reactive hyperemic index (RHI). Low RHI value indicates endothelial dysfunction. Main outcome measures- RHI values. Results- Mean gestational age at endoPAT examination was comparable between the IUGR and control group (32.5 ± 2.2 vs, 31.6 ± 3.2, respectively; p=0.21). Mean RHI was significantly lower in the IUGR group compared to the control group (1.32 ± 0.16 vs 1.51 ± 0.31, p= 0.02, respectively). As expected, mean gestational age at delivery and neonatal birth weight were lower in the IUGR group compared to the control group (35.4 ± 2.3 vs 37.3 ± 2.6 p=0.04; 1640 ± 414 grams vs 2785 ± 587 grams, p<0.001 respectively). Conclusions- Pregnant women with isolated IUGR due to placental dysfunction had impaired endothelial function.