Objective : The objectives of this study were to analyze the outcome and hemorrhagic risk of intravenous (IV) argatroban in patients with acute ischemic stroke presenting beyond six hours of ischemic symptom onset. Methods : Eighty patients with acute ischemic stroke who were admitted to the hospital beyond six hours from ischemic symptom onset were retrospectively analyzed. We could not perform IV thrombolysis or intra-arterial thrombolysis because of limited time window. So, IV argatroban was performed to prevent recurrent thrombosis and progression of infarcted area. The outcome was assessed by the National Institute of Health Stroke Scale (NIHSS) score and related hemorrhagic risk was analyzed. Also, each outcome was analyzed according to the initial stroke severity, subtype, and location. Results : The median NIHSS was 8.0 at admission, 4.1 upon discharge, and 3.3 after three months. A good outcome was achieved in 81% of patients upon discharge and 88% after three months. Symptomatic hemorrhage occurred in only two patients (3%). IV argatroban was effective regardless of initial stroke severity, subtype, and location. Conclusion : IV argatroban may be an effective and safe treatment modality for acute ischemic stroke presenting beyond six hours of ischemic symptom onset.