Recombinant granulocyte colony-stimulating factor (G-CSF) has been shown to decrease the duration of severe neutropenia, the incidence of febrile neutropenic episodes, the overall duration of intravenous antibiotic therapy, and the length of hospitalization in patients receiving myelosuppressive chemotherapy. G-CSF has also been shown to accelerate myeloid recovery after autologous and allogeneic bone marrow transplantation, and to mobilize stem cells in peripheral blood for hematopoietic rescue. However, the optimal dose, schedule, and method of administration of G-CSF in these settings remain to be standardized. This review focuses on the role of G-CSF in bone marrow and peripheral blood stem cell transplantation, and in hematopoietic stem cell mobilization.