OBJECTIVE Placental hormones such as resistin, adiponectin, ghrelin and leptin are known to have considerable role in fetal growth and there are some articles published in this area recently. Nevertheless there is a shortage of data showing association between resistin level and fetal growth; that was why we decided to conduct a study to evaluate this association. METHODS This study was approved by ethic committee of pediatric health research center and research vice chancellor of Tabriz University of Medical Sciences. In this case-control study we measured the insulin, glucose and resistin in the cord blood of neonates with gestational age of 37 weeks or more in Al Zahra tertiary hospital from March 2011 to March 2012. Thirty-nine appropriate for gestation age (AGA) neonates and 41 small for gestation age (SGA) neonates were studied. RESULTS The umbilical cord blood resistin level was not found to have significant correlation with the type of delivery [normal vaginal delivery (NVD) or cesarean-section (C-S)], neonate's gender, maternal age or body mass index (BMI). There was no significant difference in the levels of Insulin and glucose between AGA and SGA groups. Resistin level of blood cord in AGA group was 613.76±180.10 (range: 132.6-983.80 ng/ml) and in SGA group it was 1303.47±537.07 (range: 800.9-3001 ng/ml) (P<0.001). Neonates' weight in AGA group was 3162.82±407.92 g and in SGA group it was 2425.85±32.84 g (P<0.001). CONCLUSIONS In this study resistin level had reverse correlation with fetal weight in term neonates. The SGA neonates with growth insufficiency have higher resistin levels in their cord blood than AGA neonates with same gestational age. It is recommended to conduct more studies in future with larger population of patients to clarify the resistin role in neonatal birth weight.