In the 5 years since granulocyte-macrophage colony-stimulating factor (GM-CSF) was first tested clinically, a number of different strategies for its use have been evaluated in patients with malignant disease. These include using GM-CSF to support standard and high-dose chemotherapy, to accelerate myeloid reconstitution following marrow transplantation, to mobilize peripheral blood progenitor cells into the circulation for harvesting and transplantation, and in combination with cycle-specific chemotherapy drugs to enhance their cytotoxicity to leukemic cells. Early results were encouraging and data from randomized studies are now being reported. These are enabling an assessment of the value of these strategies for GM-CSF use in the management of cancer.