Cord blood is a tissue found in the placenta (afterbirth) and the umbilical cord of a newborn. It comprises highly specialized cells, such as hematopoietic stem cells, endothelial progenitor cells and mesenchymal stem cells. Cord blood contains many immunologically distinct lineage cells that, if successfully transplanted, may have great therapeutic potential in the prevention and treatment of chronic diseases ranging from cancer to congenital conditions and immune deficiency.