To define the technical factors that might contribute to hospital mortality of recipients of right lobe live donor liver transplantation (LDLT) so as to perfect the design of the operation. Right lobe LDLT has been accepted as one of the treatments for patients with terminal hepatic failure, but the design and results of the reported series vary and the technical factors affecting hospital mortality have not been known. The data of 100 adult-to-adult right lobe LDLT performed between 1996 and 2002 were prospectively collected and retrospectively analyzed. All grafts except one contained the middle hepatic vein, which was anastomosed to the recipient middle/left hepatic vein in the first 84 recipients and directly into the inferior vena cava (with the right hepatic vein in form of venoplasty) in the subsequent 15 patients. Venovenous bypass was used routinely in the first 29 patients but not subsequently. Eight patients died within the same hospital admission for liver transplantation. There was no hospital mortality in the last 53 recipients. Comparison of data of patients with or without hospital mortality showed that graft weight/body weight ratio, graft weight/estimated standard liver weight ratio, technical error resulting in occlusion/absence of the middle hepatic vein, use of venovenous bypass, the lowest body temperature recorded during surgery, the volume of intraoperative blood transfusion, fresh frozen plasma, and platelet infusion were significantly different between the two groups. However, the pretransplant intensive care unit status of the recipients, cold and warm ischemic time of the graft, and occurrence of biliary complications were not. By multivariate analysis, low body temperature recorded during operation, low graft weight/estimated standard liver weight ratio (</=0.35), and the middle hepatic vein occlusion were independent significant factors in determining hospital mortality. To achieve a uniformly successful right lobe LDLT, the right lobe graft must contain a patent middle hepatic vein. With a completely patent middle hepatic vein, a graft size of >35% of the estimated standard graft weight may be sufficient for recipient survival. Hypothermia, which predisposes to coagulopathy and is enhanced by the use of venovenous bypass and massive blood, and blood product transfusion must be avoided.