Stroke is one of the most common etiologies causing disability in developed countries. There remains no proven treatments except tissue plasminogen activator currently. Based on promising results of cell therapy in animal stroke models, efforts to apply cell therapy for patients with stroke has been made. UCB possess various stem or progenitor cells and is known to secrete neurotrophic factors to repair injured brain. This clinical research aims to determine the safety and efficacy of allogeneic UCB for stroke.