A 67-year-old woman with nephrotic syndrome as a complication of membranous glomerulonephritis associated with chronic active hepatitis B virus infection developed factor V inhibitor following emergency aortic aneurysm surgery followed by massive blood transfusions and haemodialysis. On the second postoperative day, prothrombin time and activated partial thromboplastin time increased and were unresponsive to fresh frozen plasma. Epistaxis and urethral bleeding were observed, followed by mucosal mouth bleeding. A very low factor V activity less than 5% was found and a factor V inhibitor was detected at 7.76 Bethesda Units. Treatment with corticosteroids was successful. In this patient, several conditions known to predispose to the generation of factor V inhibitor occurred simultaneously. Four months later, factor V inhibitor (225 Bethesda Units) recurred and the patient died of intracerebral haemorrhage.