Background: Excessive weight loss in newborns occurs mainly due to substantial decline in the total body water occurring after birth. The aim of this study is to determine the association of weight loss with hyperbilirubinemia in term and late preterm neonates during the early neonatal period. Methods: A hospital based prospective cross sectional study was conducted at our institution on 500 term and late preterm inborn neonates. The weight of the newborns weremeasured on a standard electronic infant weighing scale within one hour of birth and at 24 hours, 48 hours, 72 hours or till discharge. Serum bilirubin levels were analyzed for all babies at 48 and 72 hours of life by VITROS 5600 BuBc slide method. The data was analyzed and any association between significant weight loss and hyperbilirubinemia was looked for. The correlation between postnatal weight loss and serum bilirubin levels was determined. Results: Significant weight loss is neither associated with increased serum bilirubin levels at 48 hours (p= 1) nor there is a correlation between post-natal weight loss and serum bilirubin(r =0.05). Significant weight loss is not associated with increased serum bilirubin levels at 72 hours(p=0.29) and there is a no correlation between post natal weight loss and serum bilirubin levels (r=0.1). Conclusion: Significant weight loss is not associated with increased serum bilirubin levels. However early identification and correction of dehydration should be targeted upon to prevent the potential complications.