The average incidence of pulmonary embolism in routine autopsies is about 10 per cent, although higher figures have been reported in necropsies oriented particularly toward the demonstration of emboli (1–3). Since the great majority of the patients survive the first and even repeated episodes of embolization, the actual number of people hospitalized each year with this condition must exceed the autopsy figures. In our experience and that of others, however, the correct clinical diagnosis is frequently missed. Nowadays, when current therapy for pulmonary thromboembolism has been shown to improve prognosis significantly (4), early and accurate diagnosis becomes especially important. At the present time pulmonary angiography is probably the most reliable clinical test for pulmonary embolism. Our experience with pulmonary angiography is based on 98 examinations in 92 patients suspected of having recent or repeated episodes of pulmonary embolization. The purpose of this discussion is to elaborate upon the angi...