Subclavian artery aneurysms (SCAA) are relatively rare in peripheral artery aneurysm. It can rupture, thombose, embolize or cause symptoms by compression. In this article, we present a case of endovascular therapy for an intrathoracic left subclavian artery aneurysm. A 80-years-old man was referred to our department for the treatment of SCAA. Thirteen-years ago, he underwent coronary artery bypass grafting via median sternotomy. Preoperative computed tomography revealed a left SCAA which was 28 mm in diameter and patent left internal mammary artery graft. So endovascular therapy was performed. Endovascular therapy for this patient was a less invasive alternative to conventional surgical procedure.