Hemolysis from ABO incompatibility is one of the most common cause of isoimmune hemolytic disease during neonatal period. Infants with blood group type A or B , carried by blood group type O mother, will have a positive antibody because of maternal anti-A or anti-B transfer in to the fetal circulation. Ten percent of these infants will present with hemolytic disease . Most of the infant presents with unconjugated hyperbilirubinemia in the first 24 h of life and it is rarely a cause in patients who are discharged from nursery and readmit with severe hyperbilirubinemia.