Hemopoietic cell transplantation (HCT) is presently the only therapy with curative potential for myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD). Among patients with less advanced MDS, 3-year survival figures of 65-80% are achieved with human leukocyte antigen (HLA)-identical related and unrelated donors. The probability of relapse is less than 5%. Among patients with advanced MDS (> or = 5% marrow blasts), about 35-50% of patients transplanted from related donors, and 25-40% transplanted from unrelated donors are surviving in remission beyond 3 years. The incidence of post-transplant relapse is 10-35%. Criteria of the International Prognostic Scoring System (IPSS) predict relapse and survival following HCT. In patients with myelofibrosis, allogeneic transplantation is successful in 50-80%, if performed during the fibrosis stage. The success rate declines to 25-40%, if the transplant is performed after leukemic transformation has occurred. About 40% of patients with chronic myelomonocytic leukemia survive in remission after transplantation. Results obtained with low/reduced-intensity conditioning regimens are encouraging because of a low incidence of early mortality. However, retrospective analyses comparing low intensity and conventional conditioning regimens have yielded inconclusive results regarding long-term outcome. Co-morbid conditions present at the time of transplantation have a major negative effect on transplant outcome. Controlled prospective trials are needed.