High-dose chemotherapy with autologous hematopoietic progenitor-cell support is increasingly used for the treatment of hematologic malignancies and solid tumors. Over the last few years, the major source of progenitor cells for clinical use has shifted from bone marrow to peripheral blood. The current approaches on peripheral blood progenitor-cell mobilization and collection is examined. The isolation of CD34-positive cells from peripheral blood progenitor-cell grafts for tumor purging is the autologous transplant setting and for T-cell depletion in the allogeneic transplant setting is also discussed.