Hepatocyte transplantation (HT) has been indicated in patients with metabolic liver diseases and acute liver failure as a bridge or an alternative to liver transplantation. HT has the benefit of non-invasive treatment, availability of hepatocyte isolated from marginal donors and cryopreserved hepatocytes at the time of need. On the other hand, HT has the disadvantages of injury of hepatocytes after thawing, difficulty of monitoring acute cellular rejection after HT, and few supplies of hepatocytes for HT. Approximately 100 cases of HT have been reported, and infused hepatocytes were derived from deceased donors or nonheart-beating donors in all cases. In our study, hepatocytes were isolated from the remnant liver of reduced left-lateral segment graft from a living-donor. We experienced two cases of HT using hepatocytes from a living-donor for the first time worldwide. One case was neonatal ornithine transcarbamylase (OTC) deficiency, and the other was neonatal carbamoyl phosphate synthetase 1 deficiency (CPS1D). HT was performed successfully in both. In the case of OTC deficiency, the patient underwent living-donor liver transplantation from his mother 5 months after HT. In the CPS1D case, 4 months have passed since HT, and the patient is waiting for a living-donor liver transplantation. In this manuscript, we review the current situation of HT and our experience of HT using hepatocytes from the remnant liver of a reduced left-lateral segment graft in a living-donor liver transplantation.