INTRODUCTIONOrthotopic liver transplantation (OLT) has become the first choice approach for the treatment of patients with end-stage liver diseases [1] . However, despite great improvements in graft preservation, surgical skills, anesthetic techniques and perioperative management [2,3] , OLT is still associated with severe bleeding and considerable transfusion requirements, which in turn greatly contribute to the peri-operative morbidity and mortality [4] . Severe bleeding in OLT occurs for several reasons, among which hemostatic abnormalities remain a major cause [5,6] . Aprotinin, a serine protease inhibitor, is more and more commonly being used in surgeries, such as cardiac surgeries and liver transplantations, to reduce bleeding and the need for transfusions. A meta-analysis of 12 trials (n = 626) of children undergoing cardiac surgery demonstrated aprotinin reduced the proportion of children receiving b l o o d t r a n s f u s i o n s d u r i n g c a r d i a c s u r g e r y w i t h cardiopulmonary bypass, but had no significant effect on the volume of blood transfused or on the amount of chest tube drainage [7] . Similarly, a meta analysis of 13 trials (n = 506) of patients undergoing major orthopedic surgery demonstrated the pooled blood loss and the amounts of red blood cell (RBC) units (U) transfused intraoperatively and peri-operatively were significantly lower among aprotinin-treated patients than control patients. Moreover, aprotinin was not associated with an increased incidence Abstract AIM: To study the effect of aprotinin used in orthotopic liver transplantation (OLT) on the intraoperative requirement for blood products and on the incidence of laparotomy for bleeding, thrombotic events and mortality.