 Methods: Consecutive patients with acute ischemic stroke who are treated with IVT or IAT within 6 hours of symptom onset in a Swiss stroke unit will be eligible for this registry. Patients are given either intravenous rt-PA or receive IAT such as intra-arterial urokinase, intra-arterial rt-PA or mechanical endovascular recanalization techniques. Patient involvement in the registry shall not influence any treatment decision. Patients will undergo a complete diagnostic work up including a clinical neurological examination using the National Institutes of Health Stroke Scale NIHSS score on admission, laboratory examination, brain and neurovascular imaging, echocardiography, 24-hours ECG to determine stroke etiology using the Trial of Org 10172 in Acute Stroke Treatment TOAST criteria. The treating physician will initiate secondary prevention of stroke as soon as possible. All patients will be examined by CT and CTA or MRI and MRA on day 1 and in any case of clinical deterioration to exclude intracranial haemorrhage and to assess recanalization of the occluded vessel using the thrombolysis in myocardial infarction TIMI grading system. Clinical outcome will be evaluated on day 1 and at 3 months using the National Institute of Health Stroke Scale NIHSS score, modified Rankin Scale score mRS, Barthel Index BI, and assessing adverse events and quality of life. The proportion of patients with favourable outcome mRS 0 to 2 at 3 months after IVT and IAT will serve as the primary outcome measure. In addition, subgroup analyses will be performed stratified by NIHSS, location of vessel occlusion, time to hospital admission and time to treatment. Secondary outcome measures will include quality of life and the proportion of patients with an excellent outcome mRS 0 or 1 at 3 months, BI 75 to 100 at 3 months, mortality at 3 months, rapid neurological improvement during the first 24 hours, complete or partial recanalization, and symptomatic intracranial haemorrhage. 