We report a rare case of aortic dissection presenting as left hemiplegia. A 57 year-old man visited the emergency department with left hemiplegia, left facial palsy and slurred speech. Brain computed tomography showed no hemorrhage. This patient was admitted under the impression of ischemic stroke. Neck sonography the following day revealed dissection of the left common carotid artery. Aortic dissection was highly suspected. Chest and abdominal computed tomography confirmed this diagnosis. This patient was referred to a medical center for further treatment, and died two days later. We remind physicians that aortic dissection could be the cause of left hemiplegia.