A 28-year-old man visited our hospital complaining of the ulcerous lower extremity. An angiography showed the stenosis of the dorsal digital artery. The clinical diagnosis was Buerger's disease. The administration of prostaglandin I₂ (PG I₂) and antithrombotic drug were done. The ulcerous lower extremity improved. But a computerized tomographic scan of the abdomen showed the bilateral hydronephrosis incidentally. A retrograde pyelography (RP) revealed the bilateral ureteral strictures. We suspected the etiology was the retroperitoneal fibrosis associated with Buerger's disease.