Anatomic variations in the hepatic arteries were studied in donor livers that were used for orthotopic transplantation. Variations have occurred in 25% to 75% of cases. Donor livers represent an appropriate model for study because extrahepatic arterial anatomy must be defined precisely to ensure complete arterialization of the graft at time of transplantation. Records of 1000 patients who underwent liver harvesting for orthotopic transplantation between 1984 and 1993 were reviewed. Arterial patterns in order of frequency included the normal Type 1 anatomy (n = 757), with the common hepatic artery arising from the celiac axis to form the gastroduodenal and proper hepatic arteries and the proper hepatic dividing distally into right and left branches; Type 3 (n = 106), with a replaced or accessory right hepatic artery originating from the superior mesenteric artery; Type 2 (n = 97), with a replaced or accessory left hepatic artery arising from the left gastric artery; Type 4 (n = 23), with both right and left hepatic arteries arising from the superior mesenteric and left gastric arteries, respectively; Type 5 (n = 15), with the entire common hepatic artery arising as a branch of the superior mesenteric; and Type 6 (n = 2), with the common hepatic artery originating directly from the aorta. These data are useful for the planning and conduct of surgical and radiological procedures of the upper abdomen, including laparoscopic operations of the biliary tract.