A cadaver liver is divisible into two transplants by section between right and left lobes, or section between left medial segment and left lateral segment medial to the umbilical cleft. To establish the ideal basis of partition of the portal elements, an anatomic study of 33 livers was performed. It is preferable to section the left portal vein, longer and more constant than the right, the right branch of the hepatic artery, larger and more constant than the left, and the left hepatic duct because of the vascularization of the common hepatic duct. To use the length of the left portal vein, it is necessary to section all its branches to segment I and then to resect this segment. After a section between the left medial segment and the left lateral segment medial to the umbilical cleft, the left medial segment always loses its total portal venous vascularization and should be resected. Before a split-liver, cholangiography and arteriography should be performed to detect anatomical variations without performing an extensive dissection which may endanger the vascularity of the bile ducts.