OBJECTIVESNeonatal hyperbilirubinemia, or newborn jaundice, is a common condition caused by high bilirubin levels. Blood group incompatibility between mother and baby is a major cause. This study examined the link between different blood group incompatibilities and their management in newborns with jaundice.MATERIAL & METHODSThis prospective observational study included 190 neonates with hyperbilirubinemia requiring phototherapy. They were divided into two groups: control (blood group compatible) and case (blood group incompatible). Data on demographics, investigations, and management were collected.RESULTSBlood group incompatibility was present in 36.3% of cases, primarily ABO (28.9%). Rh incompatibility and ABO+Rh incompatibility accounted for 5.3% and 1.6%, respectively. DAT was positive in 32.7% of ABO incompatible cases, with anti-B more prevalent. Neonates with ABO incompatibility had the highest mean total serum bilirubin (TSB) level (13.04 mg/dL) and the largest overall decrease in TSB (-33.77%).The mean phototherapy duration was significantly longer in cases (44.1 hours) compared to controls (35.5 hours). ABO incompatible neonates had a longer average phototherapy duration (42.32 hours) compared to controls. However, ABO+Rh and pure Rh incompatible cases had highest phototherapy duration among cases. Moreover, within ABO cases, the mean phototherapy duration was higher in DAT-positive cases (46 hours) compared to DAT-negative cases (40.2 hours). Delivery mode, parity, and gender did not significantly influence phototherapy duration, but gestational age might play a role.CONCLUSIONVarious blood group incompatibilities, beyond RhD, are significantly associated with hyperbilirubinemia requiring phototherapy. ABO incompatibility was the most common cause. Neonatal jaundice is linked to blood group mismatch, with ABO+Rh and pure Rh incompatibility requiring longer phototherapy. However, ABO incompatible cases had longer phototherapy in comparison to controls. Gestational age might influence phototherapy duration.