We report a case of an overlapping ulcerative colitis and aortitis syndrome. A 28-year-old woman with ulcerative colitis in the region from the rectum to the sigmoid colon developed left anterior cervical pain. A cervical contrast-enhanced computed tomography and an arch aortography showed diffuse narrowing of the left common carotid artery and segmental stenosis of the left subclavian artery involving the orifice of the vertebral artery, which defined the diagnosis as aortitis syndrome. HLA was positive for BW 52, which is frequently found in patient with this type of overlapping syndrome. Treatment with prednisolone was begun at an initial dose of 20mg/day, with gradual tapering to 5mg/day at 11 months later, when her symptoms had subsided and laboratory findings of inflammation had disappeared. One year later, she became apathetic in mental activity, and had a poor memory. She also complained of numbness on the left side of her face. Angiography confirmed the progression of the left common carotid narrowing causing the deterioration of her cerebral ischemic symptom. A saphenous vein bypass graft was placed between the right subclavian artery and the left common carotid artery. The postoperative course was uneventful and she had complete symptomatic relief and recovered active ordinary life. Postoperative angiography revealed the well functioning bypass graft.