This chapter concentrates on inherited red cell disorders: sickle cell disease and thalassemia. Care of the patient with thalassemia involves collaboration of hematologists, endocrinologists, diabetologists, cardiologists, with occasional input from other specialities such as hepatology. The sickling disorders are a group of inherited chronic hemolytic anemias with clinical manifestations occurring as a result of the polymerization of hemoglobin S. The clinical manifestations in sickle cell disease are as a result of many interacting pathological processes including: polymerization of HbS, hemolysis and nitric oxide depletion, and vaso-occlusion. All patients with sickling disorders should be jointly managed by an obstetrician and a hematologist with interest and experience in these diseases. Since these pregnancies are high risk, patients will require frequent review by the multidisciplinary team. Deficiencies in red cell enzymes often lead to shortened red cell lifespan.