Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease in which the number of platelets decreases due to auto-antibodies against platelets. We report that thoracic endovascular aortic repair (TEVAR) was successfully performed for a thoracic aortic aneurysm complicated by ITP. The patient was a man of 77 years of age. He had a history of splenectomy due to ITP. He was admitted to our hospital with an aneurysm of the aortic arch that enlarged to a maximum minor axis of 63 mm. An operation was planned. Because of ITP, it was judged that replacement of the aortic arch using a cardio-pulmonary pump would be associated with a high risk of bleeding. Thus, 2-debranching TEVAR was selected and performed with no hemorrhagic complications. He was discharged from the hospital on the 12th day after surgery. We believe that 2-debranching TEVAR is effective for reducing perioperative bleeding in patients with ITP.