Abstract Platelet function in IUGR neonates remain a field of debate, especially in preterm subgroup. Platelet Function Analyzer (PFA-100) offers a quantitative in vitro assessment of primary, platelet-related hemostasis. Our aim was to examine platelet function using PFA-100 in term and preterm IUGR neonates and associate our results with several perinatal parameters. PFA-100 was applied on 74 IUGR neonates, 48 full-term (> 37 weeks’ gestation) and 26 preterm neonates (< 37 weeks’ gestation). Control group consisted of 118 healthy neonates. Two CTs (with COL/EPI and COL/ADP cartridges) were determined on cord blood samples for each subject. COL/EPI CTs were prolonged in IUGR (median 132s) compared to control neonates (median 112,5s), p=0.0371. Median COL/EPI CT for term and preterm IUGR neonates was 126s and 137s respectively (p=0.0013), and COL/ADP CT was 70s for term and 75s for preterm IUGR neonates (p=0.0827). COL/ADP CTs were shorter in IUGR neonates born via vaginal delivery (p=0.0065), shorter after intrapartum antibiotic prophylaxis with ampicillin (p=0.0045) and prolonged in neonates whose mothers received epidural anesthesia (p=0.032). The cause of IUGR has no impact on CTs (p>0.05 in all cases). COL/EPIand COL/ADP CTs had positive correlation (r=0.37, p<0.0012) whereas no correlation was proved between both CTs and hematological parameters in IUGR neonates. Conclusions: IUGR neonates showed impaired platelet function, with preterm IUGR neonates confronting the greater risk for bleeding tendency. Prolonged COL/EPI CTs seemed to be independent of hematological parameters, especially thrombocytopenia of IUGR neonates.