Until recently, blood that remained in the umbilical cord and placenta after delivery was routinely discarded. Now that this blood is known to contain both hematopoietic stem cells and pluripotent mesenchymal cells, there has been a substantial increase in the clinical use and research investigation of umbilical cord blood in hematopoietic transplantation and regenerative medicine. Until now, standards for collection and processing were not well established. The debate continues regarding the private banking of autologous blood for "biologic insurance" versus public banking for access by the general population. Obstetricians should support the acquisition of cord units for public banking in their geographic location where cord blood banks have established collection procedures. Issues related to cost, quality control, and the need for ethnic diversity in public banks preclude the universal collection of units from all obstetric deliveries. Directed donation of cord blood should be considered when there is a specific diagnosis of a disease within a family known to be amenable to stem cell transplantation.