From June 1990 to September 1993, our department performed 73 living-related liver transplantations in 72 patients using a graft from one of the parents. We used the left lateral segment in 46, the left lobe in 25, and the right lobe in one case. One-year survival was 89% for elective cases and 65% for emergency cases. Arterial reconstruction was performed using microsurgical techniques. This enabled us to anastomose an artery of 1 mm in diameter without postoperative thrombosis. The arterial ketone body ratio, which reflects the redox state of the liver mitochondria, was measured for evaluation of liver graft viability, the recipient's condition, and postoperative management.