Patients with acute stroke caused by atherosclerotic carotid artery occlusion (ACAO) should receive intravenous tissue plasminogen activator if they meet eligibility criteria. Patients with acute stroke caused by ACAO who are not eligible for intravenous tissue plasminogen activator should receive aspirin. Heparin or heparin-like drugs do not improve outcome and should not be used. Therapy for prevention of recurrent stroke in patients with ACAO should consist of lifestyle modifications, risk factor intervention, and aspirin. Other antiplatelet drugs should be considered in patients with contraindication to aspirin. Warfarin is not indicated. Extracranial-intracranial bypass surgery provides no benefit over medical therapy in preventing recurrent stroke in a general population of patients with ACAO or in any subgroups selected by clinical or arteriographic criteria. Extracranial-intracranial bypass surgery in patients selected by hemodynamic criteria should only be performed as part of a randomized controlled clinical trial. Other surgical or endovascular procedures have no proven value in treating or preventing stroke caused by ACAO. Asymptomatic carotid occlusion has a benign prognosis, and requires no specific treatment other than lifestyle modification and risk factor intervention.