Acute massive pulmonary embolism occluding 60-70% of the pulmonary circulation occurred in a young primipara during the 28th week of pregnancy. She was critically ill despite 40 h of heparin infusion and thrombolytic therapy with streptokinase was initiated. After a 10-h infusion she went into labor and streptokinase treatment was stopped. One hour later she gave birth spontaneously to a preterm infant in footling breech delivery. The infant did well neonatally. Streptokinase infusion was recommenced 8 h after delivery. Because of increasing blood loss on the second day after delivery, streptokinase was withdrawn after a total treatment time of 29 h. Total hemorrhage amounted to 8.9 litres. Serial perfusion lung scans showed complete resolution of the emboli and normal lung function was restored.