BACKGROUNDHaemolytic disease of foetus and newborn (HDFN) is triggered by enhanced destruction of red blood cell due to immune-mediated destruction, intrinsic abnormalities, acquired aberrations, etc. Lifespan of infant's erythrocytes are shortened by the action of placentally transferred maternal antibodies in immune-mediated HDFN.The aim of this study was to identify the frequency of maternal antibodies in neonates with hyperbilirubinaemia. Settings and Design-This was a cross-sectional study in neonates admitted to neonatal intensive care unit (NICU). Setting for the research was Dept. of Transfusion Medicine and Neonatology division of Sree Avittom Thirunal Hospital for women and children attached to Govt. Medical College, Trivandrum.