Counterflow centrifugal elutriation (CCE) separates mixed cell populations into distinct subpopulations, on the basis of different sedimentation characteristics, without impairment of cell function or yield. The advantages of this technique are the high recovery and viability of fractionated cells, as well as the rapidity and the reproducibility of results. CCE alone, or in combination with other separation methods, can provide homogeneous populations of cells for further investigations. Recently, CCE was employed in clinical studies aimed at preventing graft-versus-host disease in bone marrow transplant recipients, by depleting lymphocytes prior to bone marrow infusion. This article reviews the principles of elutriation and describes the possible experimental and clinical applications of this technique, which seems suitable for both peripheral blood (PB) and bone marrow (BM) separation.