A 50-year-old woman with aortitis syndrome complicated by aortic dissection, is reported. The dissection was observed at the level of the descending thoracic aorta by aortography and at the intimal side of the dilated aorta on CT. An aneurysm of the right subclavian artery and a diffusely thick wall of the abdominal aorta were also observed. This case suggests that the uneven wall of the aorta in aortitis syndrome might be dissected at the intimal side by dilatation.