Abstract. Hemolytic disease of the newborn is a serious immunohematological disorder caused by incompatibility between maternal and fetal blood groups. The disease develops when maternal antibodies cross the placenta and destroy fetal red blood cells, leading to hemolysis, anemia, and hyperbilirubinemia. This article examines the etiology, pathogenesis, clinical manifestations, diagnostic methods, treatment approaches, and preventive measures of hemolytic disease of the newborn. Particular attention is given to Rh and ABO incompatibility, which are the most common causes of the disease. The study highlights the importance of early diagnosis, prenatal monitoring, phototherapy, exchange transfusion, and immunoprophylaxis in preventing severe complications. The findings indicate that timely medical intervention and appropriate preventive strategies significantly improve neonatal survival and reduce the risk of long-term neurological damage. Therefore, comprehensive maternal and neonatal healthcare remains essential for the effective management of hemolytic disease of the newborn.