BACKGROUND: Alteplase, a recombinant tissue plasminogen activator (tPA), was approved for patients with acute ischemic stroke within 3 hours of stroke onset in Japan in October 2005 at a dose of 0.6 mg/kg. The aim of this study was to assess the safety and efficacy of alteplase in elderly patients in Japan. METHODS: One hundred twenty-nine consecutive patients who were admitted to our 5 hospital groups and who received intravenous tPA within 3 hours of stroke onset between January 2010 and December 2011 were divided into 2 groups by age (<80 years of age [younger group] and >80 years of age [older group]) and by treatment with or without edaravone. Clinical backgrounds and outcomes were investigated. RESULTS: The National Institutes of Health Stroke Scale score on admission was not different in both groups, but the National Institutes of Health Stroke Scale scores 7 days after stroke onset were significantly higher in the older group (score 8; P < .05) than in the younger group (score 4), and the ratio of patients with a modified Rankin Scale score of 4 to 6 was significantly greater in the older group (41.7%; P < .05) than in the younger group (22.2%). However, there was no difference in asymptomatic and symptomatic intracerebral hemorrhage rates between the younger and older groups (asymptomatic 20.2% v 18.8%; symptomatic 2.6% v 2.1%). Patients with edaravone showed a higher recanalization rate (61.9%; P < .01) and a better modified Rankin Scale score at 3 months poststroke (P < .01) than the nonedaravone group. CONCLUSIONS: These data suggest that intravenous alteplase (0.6 mg/kg) within 3 hours of stroke onset was safe and effective, even for very old patients (≥ 80 years of age), but resulted in poor outcomes relating not to tPA but to aging. In addition, edaravone may be a good partner for combination therapy with tPA to enhance recanalization and reduce hemorrhagic transformation.