High-dose therapy with autologous hematopoietic progenitor cell support is effective treatment for patients with a variety of high-risk malignancies. Accelerating of marrow recovery from near-lethal or lethal toxicity with hematopoietic cell support improves the safety and cost effectiveness of the high-dose regimens. Peripheral blood progenitor cells will soon replace marrow as the major source of hematopoietic support. This chapter reviews the techniques of peripheral blood progenitor cell collection, mobilization, purification (for tumor removal), and ex vivo expansion.