BACKGROUND Review of the literature is limited with respect to thrombotic risk in the living liver donor. This study examines inherent coagulable changes that occur as a result of the surgery. METHODS At our center, we have performed 353 orthotopic adult liver transplants in the past 4 years. Of these, 20 were adult-adult right lobe living donor transplants. All living donors are alive and doing well. Of these, eight living donors were followed preoperatively and postoperatively monitoring protein C, protein S, antithrombin III, and factor VIII levels. Levels were checked at 48 hours postoperatively, as well as at 2, 4, and 6 weeks. RESULTS All eight patients had normal levels preoperatively, although significantly low levels were identified postoperatively of these coagulation markers: protein C decreased to as low as 0%, (range 0-29; normal 50-150) within 48 hours postoperatively; protein S decreased to 3% to 40% during the same time frame (normal 50-150), and antithrombin III levels decreased to 47% to 55% (normal range 50-150%). Factor VIII levels significantly increased to >200% (normal 50- 150). All coagulation levels returned to the normal range within 4 to 6 weeks. None of the patients developed a thromboembolic event. CONCLUSIONS We observed an imbalance of low protein C, S, and antithrombin III and elevated factor VIII levels, which have been documented as thrombotic risks in adults. Our findings suggest that the imbalance in the coagulation profile after surgery may be an independent risk factor for thrombosis beyond the surgical event, a phenomenon that requires further exploration.