Surgical reconstruction of the carotid artery using a synthetic graft is rarely performed. A 71-year-old woman developed hoarseness and was diagnosed as having thyroid cancer. Computed tomography (CT) and angiography revealed an irregular thyroid tumor invading the left common carotid artery, and encasement of the artery by the tumor. Left common carotid angiography showed an irregularity of the common carotid artery wall and a dense tumor stain fed by the superior thyroid artery. Dissection of the thyroid cancer from the common carotid artery was judged to be impossible during surgery, so resection of the whole tumor together with the common carotid artery was carried out. The left common carotid artery was reconstructed using an expanded polytetrafluoroethylene (ePTFE) graft. No cerebral ischemia was evident after surgery. Postoperative CT and magnetic resonance angiography demonstrated patency of the carotid artery, and no tumor recurrence was confirmed at a 27-month follow up. The ePTFE graft appears to be a suitable synthetic graft for reconstruction of the carotid artery.