The currently used methods of monitoring liver perfusion and oxygenation after liver transplantation have major limitations in clinical use. We describe the use of a multiparameter sensor to enable continuous monitoring of liver tissue oxygen tension, carbon dioxide tension and hydrogen ion concentration in the early postoperative period in 12 patients after liver transplantation. The sensor was inserted under direct vision via the falciform ligament into the liver before skin closure. Tissue oxygen tension values decreased in the first 24 h and subsequently increased to a mean (SD) = 7.3 (2.8) kPa at 48 h after surgery. This was associated with a decrease in the degree of acidosis. There were no complications attributable to the sensor. This study demonstrates that continuous measurement of liver oxygen tension, carbon dioxide tension and pH is possible. This technique may be useful as a continuous monitor to help identify grafts at risk of ischaemia.