A 53-year-old man was hospitalized with chronic abdominal pain. A CT scan was performed and demonstrated an aortic aneurysm surrounded by a soft tissue mantle. In the laparotomy, extensive fibrotic adhesions between the aneurysm and the duodenum were discovered. This made mobilization of the duodenum and the left renal vein difficult. The aortic wall was white, thickened, and surrounded with dense fibrous tissue. The aneurysm was replaced by a Dacron graft. Histology of the fibrous tissue showed the features of chronic inflammation. He had no abdominal pain after the operation, and he was discharged in good health. In the preoperative diagnosis of inflammatory aneurysms, the CT scan is useful. We are of the opinion that the preferred treatment for inflammatory aneurysm is aneurysmectomy (or aneurysmorrhaphy) plus grafting.