The case of a 72-year-old demented woman having episodes of strokes without any risk factors for cardiovascular disease is reported. Her elder brother and sister have also had stroke episodes since their middle age. She experienced hallucinations, delusions, and recurrent headaches since the age of 55. She has gradually developed gait disturbance and cognitive impairment. Brain MRI revealed extensive leukoaraiosis and multiple lacunar infarcts in the deep white matter and brainstem. Repeated MRI incidentally disclosed fresh hemorrhage in the dorsal subcortical temporal lobe, which appeared to be asymptomatic. Anti-platelet agents were not used during disease progression. We detected G975C mutation of the Notch3 gene and diagnosed our patient's disease as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). This report suggests that arteriopathy of CADASIL could cause a hemorrhagic process, indicating that, in such a case, routine administration of anti-platelet agent to prevent recurrent ischemic stroke is not recommended.