Uterine prolapse resulting in hydronephrosis was uncommon. We report two cases of complete uterine prolapse and bilateral moderate hydronephrosis. Case 1, she was admitted due to fever with pyuria. Uterine prolapse was noted by incidental finding. Urine culture showed Escherichia coli. She received total vaginal hysterectomy, which corrected the obstruction and bladder dysfunction. Case 2, she had a history of liver cirrhosis and was denied further operation due to bleeding tendency. Renal echo and intravenous pyelography showed bilateral moderate hydronephrosis with hydroureter in the two cases. Normal renal function was found in the two cases. We suggest early diagnosis and management are necessary in order to prevent renal failure and urinary tract infection.