© 2021Objectives: We aimed to evaluate total serum calcium (TSC) and ionized serum calcium (ISC) levels and their effects on clinical outcomes in neonates underwent exchange transfusion (ET). Method: In this study, the data of newborn infants who underwent ET due to hyperbilirubinemia in a third level neonatal intensive care unit (NICU) were retrospectively analyzed. The patients were monitored by electrocardiogram during ET. Cardiac and respiratory rates, peripheral oxygen saturation, blood pressure values and clinical findings as convulsion, tremor, hypertonia, laryngospasm, cyanosis and apnea were recorded in ET observation forms. The infants with no symptoms of hypocalcemia during the procedure were not routinely given IV calcium gluconate. TSC and ISC measured at the beginning, at the end and 24 h after the end of ET were evaluated retrospectively. Results: Data of 36 newborn patients were evaluated. Median gestational age was 39 (35−40) weeks, mean birthweight was 2840 ± 841 (mean ± SD) grams. During the ET, desaturation was observed in five patients(13.9 %), sinus bradycardia in six(16.7 %), tachypnea in two(5.5 %), sinus tachycardia in one(2.8 %), and rare ventricular extrasystoles in one(2.8 %). Hypocalcaemia was not detected in any of the patients at the beginning of ET. Hypocalcemia was observed in two cases (5.5 %) at the end of ET. There was no statistically significant difference between the TSC and ISC levels at the beginning of ET, at the end and at the end of 24 h. Conclusion: As a result, routine intravenous (IV) calcium administration seems to be unnecessary provided that vital signs and neurological status are closely monitored during ET.