 Graft-versus-host disease GVHD remains the most important direct complication of hematopoietic stem cell transplantation. Methods used to prevent GVHD include diverse pharmacologic interventions and ex vivo methods of T-cell depletion, the latter being the most effective ones. Historically depletion of T-cells from the graft is associated with increased rate of graft failure, relapse of malignant disease and prolonged immune deficiency. Selective depletion of TCR-alphabeta T-lymphocytes is a new method of hematopoietic stem cell graft manipulation which is thought to conserve important cell populations, e.g. NK cells and gammadelta T cells within the graft. Preliminary results suggest that TCR alphabeta depletion ensures high engraftment rate, low early mortality and good control of GVHD. The problem of delayed immune reconstitution and life-threatening viral infections remains incompletely resolved. 