The results of treatment of pulmonary embolism with heparin (n = 34), streptokinase (n = 28) or embolectomy (n = 25) are presented. The treatment groups represented different degrees of embolization with acute embolic scores (possible maximum: 20, mean ± SD): 5 ± 4, 9 ± 3 and 13 ± 3, respectively (p < 0.0001). The post-treatment embolic score (mean ± SD) for patients with acute massive central emboli (score ≥ 9) was: 6 ± 4 (n = 7) and 3 ± 2 (n = 15) in the streptokinase and embolectomy groups, respectively, (p < 0.01). The hospital mortality was 6% (n = 2), 21 % (n = 6) and 20% (n = 5) in the heparin, streptokinase and embolectomy groups, respectively (p < 0.05). The 5-year cumulative survival (± SE) was 68%± 10, 64%± 10 and 80%±8, respectively (p: NS). The relative suvival (hospital and täte deaths, observed/expected) stratified according to acute embolic score showed the best results in the embolectomy group. Systolic pulmonary artery pressure > 60 mmHg was found in cases with a duration of symptoms > 7 days and/or with ≥ 25 anamnestic recurrent embolic episodes before diagnosis, indicative of a gradual increase in pulmonary artery pressure and of partly organized non-lyseable emboli. Embolectomy carried a low risk of complications (8% with cerebral reduction). Streptokinase treatment was associated with serious complications (18% with cerebral reduction/fatal hemorrhage). Pulmonary embolectomy should be recommended in all cases with emboli in the main brainches of the pulmonary artery. Contraindications to embolectomy are duration of symptoms of more than 7 days, several recurrent episodes and a systolic pulmonary artery pressure above 60 mmHg, indicative of older organized multiple emboli.