Bone marrow stromal cells (BMSCs) have been considered to be of an ontological lineage distinct from hematopoietic cells in the bone marrow. Numerous studies have shown that BMSCs in culture exhibit an immunophenotype negative for hematopoietic markers such as CD45, CD34 and CD11b. In this brief report, we discover that human BMSCs can be isolated by positive selection from CD45+ or CD34+ cells of whole bone marrow aspirates, but not CD11b+ fractions. Adherent cells from the CD34+ and CD45+ fractions displayed growth, morphology, surface markers, and in vitro multipotency consistent with BMSCs from whole marrow. These cells were then transplanted subcutaneously in mice and were found to support the formation of hematopoietic tissue in ectopic sites. These results suggest an unidentified link between human hematopoietic cells and BMSCs and may point to the existence of a common progenitor.