While different sorts of affection of the biliary tree by the hydatide cysts of the liver are frequent (20-30%), vascular complications are rare. That is why serious peroperative bleedings are usually caused by surgical mistakes. Bleeding caused by hydatide cyst itself is very rare, sudden, abundant, dramatic and usually lethal on the operative table. We present a 76-years-old man in whom during the operation of a huge hydatide liver cyst, sudden and abundant bleeding from the defect (2 x 0.5 cm) of the left hepatic vein caused by the cyst itself, appeared. The bleeding was successfully solved by direct suture of the defect. Three months later hepatitis B viral infection manifested apparently after numerous blood and plasma transfusions during surgery, and patient died in hepato-renal syndrome.