The incidence of ischemic stroke increases with age due to improvements in health care and living conditions. With increasing proportion of old age, the proportion of old age is rapid expansion in acute ischemic stroke patients. Young and old age groups in acute ischemic stroke patients have different risk factors and clinical features. But, many patients of old age are excluded from active treatment like thrombolysis due to hemorrhagic transformation, poorer clinical outcome etc. So we studied clinical features, risk factor, outcome in ≧80 years old patients compared with <80 years. We enrolled 1,445 patients, who diagnosed acute ischemic stroke in Chosun university hospital, from January 2013 to December 2015. Patients were divided into two groups: ≧80 years versus <80 years. We compared with two groups about risk factors, stroke subtypes, thrombolysis, complications in hospital, initial National Institutes of Health Stroke Scale (NIHSS) score, prognosis. Of the total 172 patients, 54(31.4%) patients were 80 years or older. Symptomatic hemorrhage and asymptomatic hemorrhage was not different between both groups [over 79 years patients: 4/54 (7.4%) vs. under 80 years patients: 10/118 (8.5%), p>0.302], [16.7% vs. 17.7%, p>0.701]. There were no difference in mortality and favorable prognosis at 3 months later between both groups [over 79 years patients: 5/54 (9.3%) vs. under 80 years patients: 5/118 (4.2%), p=0.290], [over 79 years patients: 13/ 21 (24.1%) vs. under 80 years patients: 56/86 (47.5%), p=0.803]. There was difference in early neurological improvement rate(improvement > NIHSS 3) and degree of improvement (NIHSS at discharge - NIHSS at admission) were significant[over 79 years patients: 24/54 (44.4%) vs. under 80 years patients: 77/118 (65.8%), p=0.012], [2.69 vs 5.55, p=0.017]. Intracranial hemorrhage(symptomatic and asymptomatic) and favorable prognosis are not different significantly between two groups. Elderly patients is not a absolute contraindication for intravenous thrombolysis. For intravenous thrombolysis in elderly ischemic stroke patients, we need more study to exclude the poor prognostic factors and to consider of gain of patients.