The authors describe new technic of non-auxiliary orthotopic transplantation of segmental liver harvested from living dogs. 32 dogs were utilized. In the donor dogs, the left medial and lateral lobes were mibilized. The left portal branch, left hepatic artery, left biliary branch and the left hepatic vein were dissected free. The segmental liver graft was perfused and cooled in-situ through the left portal vein. The recipient dogs underwent two steps total hepatectomy: First the segments I, II, III, IV and V were resected. The segments VI and VII were maintained as well as the right portal vein and the retro-hepatic inferior vena cava order to keep the splanchnic and caval flux and to avoid the spleno-cavo-jugular by-pass. The segmental liver graft was then transplanted in an orthotopic position. Termino-lateral hepatico-caval anastomosis and left porto-portal anastomosis as well as arterial and biliary reconstruction were executed. All the donors survived more than 30 days. Nine recipient dogs died during the first three post-operative days from hemorrhage (3 dogs), fibrinolysis (2 dogs), primary non function of the graft (2 dogs) and hepatic artery thrombosis (1 dog). Seven recipients survived more than 30 days.