An 80-year-old woman was referred to our hospital because of eosinophilia and thrombocytopenia. She presented with persistent pruritus and cough. Laboratory examinations showed persistent eosinophilia, and there was no underlying cause, consistent with hypereosinophilic syndrome (HES). After admission, she developed a neurological deficit, and microangiopathic hemolytic anemia. She was diagnosed with thrombotic thrombocytopenic purpura (TTP) and successfully treated with corticosteroids and plasmapheresis. Although TTP has been described in association with pregnancy, cancer, collagen diseases, infection, and drug intake, hypereosinophilia is not a well-documented cause of this disorder. To our knowledge, this is only the second case of TTP with HES, proved to be caused by ADAMTS13 inhibitor.