Adult patients with myelodysplasia, leukemia, and non-Hodgkin's lymphoma can be cured by allogeneic bone marrow transplantation (BMT). This curative effect has until now been ascribed to the intense chemoradiotherapy used to condition the recipient for transplantation. The assumption that the curative effect of allogeneic transplantation rests in the ability to deliver very high doses of chemoradiotherapy has led to the restriction of allogeneic transplantation to those recipient patients whose overall status would permit the use of such intense conditioning. As a result, HIV positivity has generally appeared as an exclusion criteria to allogeneic transplantation for hematologic malignancies. Additionally, early studies of allogeneic BMT in HIV patients suggested no benefit in controlling the progression to AIDS.