Recently, several groups have begun to administer granulocyte colony-stimulating factor (G-CSF), a hematopoietic growth factor, with or without dexamethasone to mobilize peripheral blood neutrophils. Granulocyte colony-stimulating factor (600 μg subcutaneously) and dexamethasone (8 mg orally) given 12 hours before standard leukapheresis routinely results in the collection of approximately 80 × 109granulocytes. This number of cells is sufficient to increase the neutrophil count of a severely neutropenic patient to normal and restore the recipients’ ability to develop a neutrophil response in tissues. Several trials are ongoing to establish the clinical benefit of this new approach to supportive care for neutropenic patients.