Graft-versus-host disease (GVHD) remains the main problem after the allogeneic bone marrow transplantation. It is extremely complicated to maintain the finely organized set of immunologic events in order to prevent GVHD and thereby retain the graft-versus-leukemia effect. There are an increasing number of immunosuppressive drugs available for prevention and treatment of GVHD. Cyclosporine, sirolimus, FK506, mycophenolate mofetil and CTLA-4 Ig prevent activation of donor T-lymphocytes, while daclizumab and infliximab act on effector cells. It is hard to believe that it would be possible to prevent and cure GVHD with a single agent; combination of immunosuppressive drugs that act on different phases of GVHD induction seems promising.