We present a case of polypoid endometriosis of the ureter that showed bilateral polypoid intraluminal masses in the lower part of the ureter mimicking ureteral fibroepithelial polyps, arising with a background of pelvic endometriosis and a history of gonadotropin releasing hormone (GnRH) therapy. Magnetic resonance imaging revealed the masses to have high signal intensity on T2-weighted imaging. The location and bilaterality of the polypoid intraluminal masses are considered useful points in the differential diagnosis of fibroepithelial polyps.