Allogeneic bone marrow transplantation is an effective curative therapy for both malignant and heritable diseases. The use of genetically altered autologous hematopoietic stem cells (HSC) is being increasingly investigated as a treatment for a variety of non-malignant but significantly morbid diseases, including hemoglobinopathies, immunodeficiencies and autoimmune diseases. Other hematopoietic cells capable of proliferation, such as antigen-specific T cells and dendritic cells, have also been used for adoptive immunotherapy. Genetic procedures to modify these various therapeutic cells so that they can be selectively amplified either in vitro or in vivo could enhance their efficacy. For example, HSC that contain a gene that confers a survival, selection or growth advantage may enhance their engraftment. Such enhancement could be expected to reduce graft failures and the intensity of the required conditioning regimen, thereby decreasing the toxicities of transplantation. In this review, the functions of cytokine receptor transgenes coding for erythropoietin receptors (EpoR) are analyzed. The characteristics of these transgenic cells and animals are discussed with regard to the possible therapeutic use of EpoR transgenes in the transplantation of hematopoietic cells.