Purpose: We evaluated clinical background and outcome of ischemic stroke patients with mild symptoms treated with intravenous recombinant tissue plasminogen activator (rt-PA). Methods: We analysed clinical and radiological data of 159 ischemic stroke patients treated with intravenous rt-PA therapy in our stroke center from Jun. 2006 to Mar. 2015. Among them, 14 patients had National Institute of Health Stroke Scale (NIHSS) score ≤4 points (mild group) before rt-PA and 145 patients had NIHSS score >4 (severe group). Results: There were no differences in the sex or age between both groups.Cardioembolic stroke were more frequent in the severe group, and atrial fibrillation was significantly frequent in the severe group. NIHSS score 24 hours after the rt-PA treatment was significantly good in the mild group. The cases which NIHSS 24 hours later improved to point zero were significantly frequent in the mild group. Compared to patients in the severe group, patients in the mild group more often had good outcome at discharge [Modified Rankin Scale (mRS): 0-1]. Six patients had hemorrhagic complications in the severe group while no patient had in the mild group. Conclusion: Intravenous rt-PA treatment is beneficial for patients with mild deficit.