Autologous and allogeneic hematopoietic cell transplantations (HCT) after high-dose conditioning are curative for many patients with hematologic malignancies. The major limitation of autologous HCT is disease recurrence, while the problem with allogeneic HCT is the restriction to relatively young and otherwise medically fit patients because of complications from high-dose therapy coupled with those from graft-versus-host disease (GVHD). The well-described benefits of graft-versus-tumor (GVT) effects have stimulated the development of conditioning regimens with attenuated doses of chemoradiotherapy that may provide both a degree of cytoreduction before allografting (reduced intensity) and facilitate allogeneic cell engraftment through immuno- suppression (nonmyeloablative). Both reduced-intensity and nonmyeloablative approaches seek to exploit GVT activity of donor cells to eradicate cancer. Because of intrinsic or acquired insensitivity of some malignancies to standard dose chemotherapy and the limitations of GVT effects in eradicating large tumor burdens, high-dose autologous HCT has been used before reduced-intensity and nonmyeloablative allogeneic HCT. This approach appears to improve response rates for malignancies such as multiple myeloma and lymphoma, while avoiding morbidity and mortality of high-dose allogeneic HCT. This review details the rationale, benefits and limitations of this approach.