In 1995, the National Heart Lung and Blood Institute (NHLBI) solicited requests for a proposal (RFP) entitled "Transplant Centers for Clinical Research on Transplantation of Umbilical Cord Stem and Progenitor Cells." Three banks, six transplant centers, and one medical coordinating center (MCC) (Table 1) were funded with the overall goal of banking cord blood units (CBU) using a single manual of operations. Furthermore, the clinical protocols to evaluate the transplant outcome for adult and pediatric recipients of these well-characterized CBU would be analyzed in a uniform fashion. Because of the intense interest of the transplantation community in the policies and procedures for cord blood collection and processing, the principal investigators of the cord blood banks (CBB) and NHLBI elected to submit for publication the rationale and an abridged, but detailed, version of the standard operating procedures (SOP) developed between October 1996 and July 1998 prior to the initiation of the clinical protocols to be performed with these CBU. As the SOP will be refined over time, the complete SOP and subsequent amendments will be published and continually updated on the websites from the MCC - The EMMES Corporation (www.EMMES.com). All forms referred to in this document may be obtained from the EMMES website. It is hoped that the publication of this document will lay down a framework that will not only facilitate the development of other CBB but also help us more rapidly define what constitutes an "acceptable" CBU product. The document is detailed according to the following sections.