The incidence of chronic MPD and MDS could be reduced considerably if relevant environmental factors could be identified and eliminated, but this seems an unlikely prospect for the foreseeable future. More probable is the likelihood that the molecular basis of the various chronic MPD gradually will be elucidated such that specific inhibitory molecules analogous to imatinib may be designed for each disease or each subtype of disease. Combinations of inhibitory molecules may prove especially useful. There is ample scope for improving the clinical results of allogeneic stem cell transplantation, which in theory could "cure" most patients with MPD or MDS. In this regard, reduced-intensity conditioning allogeneic stem cell transplants seem promising. One possibility is identification and exploitation of the basic mechanism underlying the graft-versus-leukemia effect for eradication of minimal residual disease without the need for allografting.