The case of a middle-aged man is described, who was admitted because of intermittent back pain and a high sedimentation rate. Abdominal sonography and arteriography showed a large aneurysm of the splenic artery, but failed to recognize the aneurysm as of inflammatory origin. However, the inflammatory nature of the aneurysm was evident on computer tomography scan. Intraoperatively the inflammatory origin of the aneurysm was confirmed. A saphenous vein graft was implanted and marsupialization of the aneurysm performed. Histology could clearly verify the diagnosis of an inflammatory aneurysm. This report indicates the possibility of inflammatory changes occurring in connection with a visceral artery rather than solely with the abdominal aorta.