Adult living donor liver transplantation has been widely expanded in the world after the introduction of right lobe grafting. This expansion was hampered by the issues of morbidity and mortality in living donors undergoing right lobectomy. Some institutions, especially in Japan, were extending Adult LDLT using a left lobe graft for selected patients. A partial liver graft unable to meet the functional demands of the recipient results in liver failure including coagulopathy, ascites, prolonged cholestasis and encephalopathy, often associated with pulmonary and renal failure, and frequently leads to death of the recipient in the absence of re-transplantation. This ill-defined clinical picture is considered to be primarily linked to an insufficient graft size, and hence termed ‘small-for-size-syndrome’ (SFSS). In Japan, multi-centre studies have shown that the incidence of postoperative complications was higher for right lobe donation than for left lobe donation, and that the incidence of biliary tract complications was also higher for right lobe donation.