The clinical-angiologic data and the clinical outcome in 66 patients with acute vertebro-basilar thrombosis treated with antiplatelet agents, anticoagulants, or fibrinolytic agents are presented. Forty-three patients were treated with local intraarterial infusion of streptokinase or urokinase proximal to the thrombotic occlusion; 14 patients in this group (33%) survived, only one of whom was in deep coma when therapy was started. Twenty-three patients did not receive fibrinolytic therapy; 4 of these patients (17%) who exhibited mild brainstem-related symptoms survived. This study implies that early diagnosis and treatment in vertebrobasilar stroke in progression may achieve improved survival.