The present invention provides compositions and methods of using embryonic-like stem cells that originate from a post-partum placenta with conventional cord blood compositions or other stem or progenitor cells. The embryonic-like stem cells can be used alone or in a mixture with other stem cell populations. In accordance with the present invention, the embryonic-like stem cells may be mixed with other stem cell populations, including but not limited to, umbilical cord blood, fetal and neonatal hematopoietic stem cells and progenitor cells, human stem cells and progenitor cells derived from bone marrow. The embryonic-like stem cells and the mixed populations of embryonic-like stem cells and stem cells have a multitude of uses and applications, including but not limited to, therapeutic uses for transplantation and treatment and prevention of disease, and diagnostic and research uses.