Hematopoietic progenitor cells can be mobilized from the bone marrow microenvironment into the peripheral blood following treatment of patients with myeloid cytokines (GCSF, GMCSF, IL3), a CXCR4 antagonist (Plerixafor) and/or following a hematopoietic recovery from cytotoxic chemotherapy. The hematopoietic stem and progenitor cells are contained within the mononuclear cell fraction of peripheral blood and can be collected by apheresis in which the cellular constituents of the blood are separated on the basis of their buoyant density. Modern apheresis allows processing of five or more blood volumes (24 L or more) over a 4-5-h period to efficiently remove and separate more than 70 % of the CD34 positive cell progenitors present to blood. Management of a patient undergoing apheresis requires careful attention to venous access, calcium placement to counteract the effects of the citrate uses anticoagulant and hemodynamic monitoring. The principles of setting up the COBE spectra and its operation are reviewed. Management of common toxicities including hypocalcemia, allergic reactions, and vasovagal reactions are described in the next chapter.