Noncalculous ureteral obstructions in Crohn's disease are often asymptomatic and unidentified. Occurring in about 3% of patients, they occur on the right side in more than 70% of cases, because of frequently associated ileocecal disease. If they are associated with inflammation or fibrosis of retroperitoneal periureteral fat nephrectomy may become necessary. Conservative treatment should be considered first, with urine drainage (ureteral stent, or percutaneous nephrostomy), diet, and corticotherapy. However bowel resection is often necessary during follow up. If this fails to cure the ureteral obstruction, ureterolysis should be performed. We report the case of a 32 year old woman with noncalculous ureteral obstruction revealing Crohn's disease.