Summary Retroperitoneal fibrosis, either idiopathic or associated with aortic inflammatory aneurysm, is a chronic fibrotic disease that causes progressive obstruction of ureters and vessels around the lower abdominal aorta. Treatment is often difficult (surgery) or hazardous (steroids). We report a case of a woman with retroperitoneal fibrosis associated with aortic inflammatory aneurysm, who was successfully treated with oral tamoxifen.