The identification of genetic mutation that causes sickle cell disease 35 years ago has not yet led to a widely applicable, specific therapy that corrects the underlying abnormality of hemoglobin. Nevertheless, recent progress in understanding the pathophysiology and natural history of sickling disorders has led directly to important prophylactic and supportive therapies that have markedly reduced morbidity and prolonged life expectancy. This is particularly true for manifestations of sickle cell disease that result from damage to the spleen, lungs, and brain. New strategies for specific therapy, including expanded use of chronic transfusions, bone marrow transplantation, and hydroxyurea, now offer hope for prevention of many or all of the hemolytic and vaso-occlusive manifestations of sickle cell disease.