Thyroid hormones and thus iodine are essential for brain maturation, moderate to mild iodine deficiency is the main cause of preventable cognitive impairment. The number of surviving LBW has been associated with an increased prevalence of transient disorders of thyroid functions. Cord blood was collected from 90 neonates after clamping the cord. 59 of them were preterm of LBW, control group including 31 full term neonates weighting more than 2500 gm as a control group, the blood samples were subjected to FT3, FT4 and TSH by (RIA). Our studies revealed that preterm neonates had lower levels of FT3, increased levels of TSH and no significant changes in the level of FT4 in comparison with the control group. We also found that 53% of LBW neonates with significant low thyroid hormones had hyaline membrane disease and respiratory distress.