To better define the demographics, urothelial distribution and typical gross anatomic and radiologic appearances of fibroepithelial polyps of the ureter in children. We reviewed 15 cases of fibroepithelial polyps of the ureter with hydronephrosis from the archives of our department. Data were collected from radiographic studies, gross anatomic pathology and pathology and radiology reports and categorized by age, sex, clinical presentation, lesion size and location. The mean patient age was 9.1 years, and 80% were male. All of them presented with hematuria and/or flank pain. The polyps were located in the upper ureter or ureteropelvic junction (UPJ) and pelvis. Of the polyps, 60% were multiple polyps or filiform, and 40% were single or bilobed and 1-6 cm in size. Only four cases showed typical filling defect on intravenous urography. In five cases, sonography showed a mildly echogenic structure extending into the ureter from the renal pelvis. Enhanced CT revealed soft tissue filling UPJ or/and proximal ureter in six cases, and hydroureter was found in one case by three-dimensional (3D) image. Fibroepithelial polyps were diagnosed in all cases by postoperative histological examination. Fibroepithelial polyps are the most common benign tumors of the ureter. Congenital factor may be associated with the origin of fibroepithelial polyps in children. The preoperative diagnosis of ureteral polyps is difficult. A history of flank pain, hematuria or both, other than abdominal mass, light-to-moderate hydronephrosis with soft-tissue in UPJ or upper ureter, shown by sonography and radiological examination, may help in the diagnosis of ureteral polyps in children. Ureteral polyps should be recognized as an important etiology for hydronephrosis in children.