A 43-yr-old woman was operated for recurring hydatid cysts of the liver. One of the cysts was located in segment 8 adjacent to both inferior vena cava and right hepatic vein. During the operation, after application of traction on the liver the patient suddenly went into cardiac arrest. After applying open heart massage a Trendelenburg operation was performed, revealing a massive embolus of echinococcal material into the paracentral branches of the pulmonary artery. Resuscitation was unsuccessful. In the literature only four similar cases have been described. The conclusions from these deaths are that an adequate incision is mandatory, no traction on the liver should be necessary, and total vascular exclusion of the liver before cyst drainage and extracorporal bypass are necessary. Interventional techniques should be avoided.