A case of severe acute intravascular haemolysis occurring after surgical repair of an abdominal aortic aneurysm in a 60-year old patient is reported. The operative conditions were difficult, requiring three laparotomies within 24 h, with rapid and profuse transfusion : 20 units of red blood cells, 31 of colloids, 11 units of fresh frozen plasma, 31 of diluted albumin and 41 of cristalloid solution. Evolution of the haemolysis became rapidly favourable under symptomatic treatment : forced diuresis (11.91 per 24 h) and alkalinization. None of the classic complications (acute renal failure, disseminated intravascular coagulation) arose. After review of various causes of severe acute intravascular haemolysis, its origin was probably mechanical in this case.