A serious hazard to patients during orthotopic liver transplantation is hyperkalemia. Although the most frequent and hazardous hyperkalemia occurs immediately after reperfusion of the newly transplanted liver, morbid hyperkalemia could happen in the other phases during orthotopic liver transplantation. However, pre-anhepatic hyperkalemia during orthotopic liver transplantation is rare. This report describes one such patient, who without transfusion, developed severe hyperkalemia during pre-anhepatic phase. The variations in serum potassium concentration of the present case indicate that it is necessary to take care of the changes of serum potassium concentration not only during reperfusion but also during the other phases of the liver transplantation.