Two cases of endometriosis causing ureteral stenosis are reported. Case 1. A 46-year-old woman was hospitalized with the complaint of right flank pain. Intravenous pyelography showed right hydronephrosis and retrograde pyelography revealed ureteral stenosis at the distal third ureter. Exploration revealed an abnormal periureteral mass, which was excised together with the distal part of the ureter. A right ureteroneocystostomy was performed with the Boari technique. Case 2. A 39-year-old woman was hospitalized with the complaint of pain in the left lower quadrant. A left retrograde pyelography showed stenosis of the ureter at 4 cm proximal of the bladder. An exploratory laparotomy revealed blue berry spots on the left side of the uterus and dense fibrous tissue around the ureter, which was successfully dissected out. The pathological diagnosis of both cases was extrinsic ureteral endometriosis. Ureteral endometriosis has rarely been described and the literatures on 30 cases reported in Japan were reviewed.