Recently, umbilical cord (UC) and UC-derived mesenchymal stromal cells (UC-MSCs) have attracted much attention for many reasons, including (1) abundant sources and ease of collection, storage, and transport; (2) little ethical controversy; (3) multipotency to differentiate into various cell types; and (4) low immunogenicity with significant immunosuppressive ability. In this review, we provide a brief introduction to UC and UC-MSCs in terms of characteristics, isolation, and cryopreservation, as well as emphasizing their potential clinical application in regenerative medicine and immunotherapy.