After extensive preclinical work, hematopoietic cellular therapy has recently entered a new era of clinical trials involving ex vivo cultured cells. The evolution of hematopoietic cell culture from clonogenic assays to large-scale static culture systems and bioreactors, and the identification and production of hematopoietic growth factors, have in part made this possible. In addition, murine models have demonstrated encouraging results with regard to the feasibility of infusing cultured cells, as well as to the potential efficacy. Several trials have recently been published utilizing ex vivo generated hematopoietic progenitors and myeloid progenitors, and are reviewed here. The field of clinical hematopoietic cellular therapy, while still in its infancy, is progressing rapidly, and promises to offer improved therapeutic options.