A detailed coagulation and thromboelastographic study was done on the first 50 liver transplantation procedures performed at the Mayo Clinic between March 1985 and June 1986. Most of the patients suffered from primary sclerosing cholangitis, primary biliary cirrhosis, or chronic active hepatitis. Seven patients required a second liver transplantation, and six patients died, none intraoperatively. Most of the patients had distorted hemostatic mechanisms preoperatively, as would be expected because the liver generates most of the clotting factors. The outstanding exception was factor VIII, which was usually in the high-normal range or even more elevated. Substantial deterioration of coagulation factors occurred regularly during reperfusion of the donor liver. In some instances, this trend was corrected within 1 hour, but platelet counts continued to decrease, and some coagulation factors rebounded only partially. Because thromboelastographic tracings are quickly available to the liver transplant team and because they tend to forewarn of impending hemostatic problems, we believe that thromboelastography is a reasonably effective procedure for monitoring coagulation during liver transplantation.