Bone marrow transplantation is accepted as potentially curative therapy for a variety of patients with hematologic malignancies and other disorders. The most important causes of morbidity are infections and bleeding secondary to prolonged cytopenias. Granulocyte colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) have been shown to potentially enhance bone marrow engraftment which has translated into reduced morbidity and mortality. Additionally, growth factors such as G-CSF and GM-CSF may increase numbers of circulating peripheral progenitor cells to serve as the source of "marrow" for transplantation. This review summarizes the current available data using G-CSF and GM-CSF in bone marrow transplantation and discusses potential areas of study with additional cytokines.