Background Environmental factors and growth disturbances, either intra-uterine, or post-natal, can result in permanent changes in tissues and also long-term effects that may present themselves as pathological conditions in adulthood, including increased incidence of insulin resistance, impaired glucose tolerance, and also higher likelihood for diabetes mellitus. The triglyceride to glucose index (TyG) and triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-c) have been proposed as reliable and simple alternatives for the evaluation of insulin resistance. To date, there was limited data regarding the TyG index and TG/HDL-c ratio in the perinatal period of neonates. We aimed to investigate the possible relationships between HOMA-IR, TyG index, and TG/HDL-c in the cord blood of neonates. Materials-Methods One hundred and six pregnant women with singleton gestation who gave birth to full-term, normal-weight Turkish neonates without fetal distress were included in the study. The samples of maternal serum and cord blood in neonates were obtained after delivery. Results Mean TyG index was 3.71 +/- 0.38 and the mean TG/HDL-c ratio was 3.12 +/- 3.00 in this group. Correlations were found between maternal age and neonate glucose levels and HOMA-IR (p < .05). HOMA-IR was negatively correlated with triglyceride, TG/HDL-c ratio, TyG index + TG/HDL, and positively correlated with HDL and TyG index. Conclusions Our study indicates that the TyG index and TG/HDL-C may be used as an indicator of insulin sensitivity in the perinatal period of neonates. However, the validity of these results should be tested in other centers with a larger neonate population in order to evaluate whether ethnic and racial diversity influence these relationships.