The liver cell is a unique fully functional metabolic unit that can be used for liver regenerative medicine to restore function in the diseased liver. The aim is to prevent progression and the need for the more radical treatment of end stage disease, which is currently orthotopic liver transplantation. This latter procedure is heavy, irreversible, and limited by organ shortage. Mature liver cell – hepatocyte - transplantation has shown short to medium-term efficacy to correct miscellaneous inborn errors of metabolism. The proof of concept has been established, although this procedure has not so far reached full success, with a limited durability of the functional benefit. Hepatocyte procurement is also restricted by organ shortage, and can hardly be stored due to poor resistance to cryopreservation. Alternative cell sources are therefore needed for the development and wider accessibility of cell based liver regenerative medicine. Beside safety, the main challenge for these alternative cells is to acquire the same level of functionality once implanted in the target organ. In this respect, liver progenitor cells may have some advantages over stem cells derived from other tissues.