A retrospective study of fatal pulmonary embolism (FPE) was carried out in 1,324 cases of total hip replacement (THR), performed during 1969 to 1978. Dextran 70 (Macrodex 6 per cent in saline. Pharmacia AB, Sweden) was given as thromboembolic prophylaxis. Sixteen patients died within 3 months. Autopsy was performed in 14 cases. Nine died from embolism, which makes an incidence of 0.7 per cent. Autopsy was performed in 8 of these cases. Seven patients died during the second and third week. Five patients had complained of acute chest pain and 4 of them had chest radiograms taken, which were normal. Only one patient had clinical symptoms of deep vein thromboses. Perfusion lung scan was performed as a screening procedure in 3 cases, all of them showing defects typical of pulmonary embolism. Four patients died from FPE, despite heparin therapy for 3-5 days. A comparison between patients with FPE and a control group showed that premonitory attacks of acute chest pain and previous operations for orthopaedic reasons were significantly more common in patients with FPE (P less than 0.001 and P less than 0.05), respectively). No difference could be found between the groups concerning blood loss, amount of transfusion, sex, operated side, type of prosthesis and weight.