A retrospective study was undertaken of all surgical patients in Malmö, Sweden, during the period 1951-1980, in whom pulmonary emboli were found at autopsy. The autopsy rate was high throughout the period, ranging from 73 to 100 per cent. Of 5477 patients who died during the period, 1274 had pulmonary emboli (23.6 per cent), 349 of which were considered fatal, 353 contributory to death and 572 incidental. Fifty-one per cent of the patients were not operated upon. The number of contributory and incidental emboli increased over the period, to some extent probably reflecting greater thoroughness in postmortems. The frequency of fatal pulmonary emboli decreased in the last 5 year period. Pulmonary embolism was more rare in patients under 50 years of age. The proportion of females increased. In 24 cases major embolism emanated from thrombi around central venous catheters. This retrospective analysis of a large number of patients shows that pulmonary embolism continues to be a major cause of death in surgical patients, and in Malmö as common a cause of death in operated as in nonoperated patients.