Aim: The aim of this study was to analyze the expression levels of plasma soluble Fas (sFas) and soluble Fas ligand (sFasL) in patients with orthotopic liver transplantation (OLT) procedures routinely performed without venovenous bypass. Methods: The sFas and sFasL were analyzed in the blood of 20 consecutive patients who underwent transplantation. Blood amples were drawn from the radial artery at serial time points before, during, and after surgery. Plasma levels of sFas and sFasL were detected by Enzyme Linked-Immuno-Sorbent Assay. Plasma aspartate transaminase (AST) and alanine transaminase (ALT) were assayed by routine clinical chemistry esting. Results: Marked elevation of plasma AST and ALT were detected at the reperfusion and postoperation time points (P < 0.001), with a peak on the first postoperative day. The mean plasma concentration of sFas and sFasL remained unchanged from preoperative to anhepatic phase (T1 to T3) (P P 0.268). The sFas and sFasL concentrations were significantly higher at 15 and 60 min after reperfusion compared to the preoperative value (P 6 0.048). Postoperatively, sFas and sFasL concentration were decreased to preoperative levels on the first postoperative day (PP 0.127). Conclusion: The sFas and sFasL seem to be involved in reperfusion injury during OLT. he understanding of Fas may provide new insights into the mechanisms of ischemia/reperfusion injury during OLT.