Abstract Introduction: Neonatal hyperbilirubinemia is the most common clinical finding noted during the first seven days following birth. Amongst all the modalities available for management of neonatal hyperbilirubinemia, phototherapy is proven to be the safest. However, like any other intervention, phototherapy too has some of its own side effects. Aim & objectives: To estimate and compare alterations in serum electrolytes of healthy term neonates before and after phototherapy. Material & methods: A hospital based prospective observational comparative study was conducted over a period of 18 months in the department of Pediatrics on 110 healthy term neonates with unconjugated hyperbilirubinemia who were subjected to phototherapy as per American Academy Pediatrics guidelines. Electrolytes including sodium, potassium, chloride and calcium were analyzed from serum using standard laboratory techniques. Results: The mean sodium, chloride, potassium and calcium levels before phototherapy was 141.3±2.69 meq/L, 102.2±2.98 meq/L, 4.43±0.52 meq/L, 9.14±0.46 mg/dl and after phototherapy was 140.5±2.70 meq/L, 102.0±2.93 meq/L, 4.23±0.48 meq/L and 8.09±0.55 mg/dl respectively. All were found to be statistically significant (p-value <0.05); although none were clinically significant and conveyed no symptom of dyselectrolytemia in this study. Conclusion: This study shows that neonates exposed to phototherapy are at a risk of developing electrolyte imbalances and consequently their complications. Hence, close monitoring of such babies are needed to prevent imbalances and their untoward consequences.