Liver transplantation is a relatively new procedure in which unusually large quantities of blood are used. Blood use in 68 adult and 49 pediatric liver transplants was reviewed. The median (range) intraoperative red cell use for adults and children was 28.5 (3-251) and 11 (2-55), respectively. Blood use closely correlated with the patient's primary diagnosis. Adult patients with primary biliary cirrhosis and carcinoma used about one-half as much blood as those with a diagnosis of sclerosing cholangitis, hepatitis, or cirrhosis. Patients in the former diagnostic groups also had better survival rates. Total red cell use for the patient's entire hospitalization was about twice that used during surgery. Fresh-frozen plasma use paralleled red cell transfusions, but platelet use was modest. These data can serve as a baseline in helping other hospital transfusion services prepare for the advent of liver transplantation in their institutions.