Twenty-four patients with symptoms of arterial occlusive disease were given streptokinase. Those with sudden onset of symptoms usually demonstrated intravascular thrombosis amenable to streptokinase-induced thrombinolysis. Those with gradual onset of arterial insufficiency had atherosclerotic occlusion for which streptokinase was of little benefit. Contraindications to streptokinase were (1) less than ten days postoperative, (2) severe hypertension, (3) liver disease, (4) recent cerebrovascular accident, and (5) blood dyscrasias. It was concluded that measurement of blood, fibrinogen, and thrombin clot time were necessary to control dosage; post-infusion arteriograms were necessary to control the result, and elective operation was sometimes necessary to correct the causative lesion. It was found helpful in (1) the poor-risk patient, (2) the patient with an active wound infection, (3) the patient whose thrombi are inaccessible, and (4) the complicated clinical situation in which operation would be hazardous.