A cord blood bank is a facility which stores umbilical cord blood for future use. Both private and public cord blood banks have developed since the mid- to late-1990s in response to the potential for cord blood transplants in treating diseases of the blood and immune systems.

Public banks accept donations to be used for anyone in need. Unlike private cord blood banking, public cord blood banking is supported by the medical community. However, there are very strict regulations which public banks need to follow in order to enable the donated units to be added to a registry. Generally, an expectant mother interested in donation should contact the bank before the 34th week of pregnancy. The National Marrow Donor Program has a list of public cord blood banks on their website. Once the blood is donated, it loses all identifying information after a short period of initial testing. Families are not able to retrieve their own blood after it has been donated, but, as discussed below, it is very unlikely that they would be able to use the sample themselves.

A blood bank is a cache or bank of blood or blood components, gathered as a result of blood donation, stored and preserved for later use in blood transfusion. The term "blood bank" typically refers to a division of a hospital laboratory where the storage of blood product occurs and where proper testing is performed to reduce the risk of transfusion related events. It is important for a blood bank to pass all the eligibility guidelines as mandated by the National Health Service (NHS) in Britain and the Food and Drug Administration (FDA) in the United States. The safety and reliability should also be a consideration too. This includes compatibility testing for transfusion and may include blood donation processing, depending on the capabilities of the facility.

Most hospital blood banks also perform testing to determine the blood type of patients and to identify compatible blood products for blood transfusions, along with a battery of tests (e.g. disease) and treatments (e.g. leukocyte filtration) to ensure and enhance quality. Some such procedures can be done "upstream" by the collecting agency, or a contracted laboratory. The increasingly recognized problem of inadequate efficacy of transfusion and post-transfusion complications raises the importance of quality testing and screening; U.S. hospitals spend more on dealing with the consequences of transfusion-related complications than on the combined costs of buying, testing/treating, and transfusing their blood.

Umbilical cord blood is blood that remains in the placenta and in the attached umbilical cord after childbirth. Cord blood is collected because it contains stem cells, which can be used to treat hematopoietic and genetic disorders.

Cord blood is obtained by syringing out the placenta through the umbilical cord at the time of childbirth, after the cord has been detached from the newborn. Cord blood is collected because it contains stem cells, including hematopoietic cells, which can be used to treat hematopoietic and genetic disorders. One unit of cord blood generally lacks stem cells in a quantity sufficient to treat an adult patient. The placenta is a much better source of stem cells since it contains up to ten times more than cord blood. Some placental blood may be returned to the neonatal circulation if the umbilical cord is not prematurely clamped. According to Eileen K. Hutton, PhD, and Eman S. Hassan, MBBch, cord clamping should be delayed a minimum of two minutes to prevent anemia over the first three months of life and enriching iron stores and ferritin levels for as long as 6 months. (Ref. "Late vs Early Clamping of the Umbilical Cord in Full-term Neonates," JAMA, March 21, 2007) If the umbilical cord is not clamped, and it is not during an extended-delayed cord clamping protocol, a physiological postnatal occlusion occurs upon interaction with cold air, when the internal gelatinous substance, called Wharton's jelly, swells around the umbilical artery and veins.