The human recombinant hematopoietic growth factors have attracted widespread interest because of their potential efficacy in a number of clinical settings. Recombinant human erythropoietin is now an established therapy to treat and prevent the anemia associated with chronic renal failure in children and adults. This agent also shows extraordinary promise to stimulate erythrocyte production and reduce transfusion requirements in premature infants. Granulocyte and granulocyte-macrophage colony-stimulating factors stimulate the production and function of myeloid cells and have provided major clinical benefit to children with congenital disorders of neutrophil production. The myeloid growth factors also show great promise in reducing the duration and severity of neutropenias associated with cytotoxic cancer treatment and in improving granulocyte production in patients with human immunodeficiency virus infections.