We are reporting a case of an acute thromboembolic obstruction of the aortic bifurcation in a 66-year-old patient undergoing coronary artery bypass grafting with extracorporeal circulation. After declamping of the aorta, the arterial pressure measured in the femoral artery suddenly dropped, whereas the pressure measured in the aortic cannula and in both radial arteries stayed normal. Transoesophageal echocardiography was performed to exclude an acute aortic dissection. While the patient always had a constant sinus rhythm, an angiography following the end of surgery, showed a complete obstruction of the abdominal aorta. Subsequent embolectomy through bifemoral arteriotomies was performed and a histologically fresh embolus (6,5 g in weight) was extracted. Neither the pre- and intraoperative echocardiography, nor the preoperative ventriculography showed signs of an intracardiac thrombus. Insufficient anticoagulation and a lack of inhibitor potential were almost excluded. Considering the histological findings, we assumed that the embolus was formed intraoperatively. Without further complications the patient left our department on the 8th postoperative day.