A case of tubulovillous adenoma arising in an augmented bladder is described. Ureteroileal substitution and ileocystoplasty was performed when the patient was 18 years old. She noticed gross hematuria 44 years after the surgery. Cystoscopy revealed a non-papillary multiple tumor at the site of ileovesical anastomosis and transurethral resection biopsy was performed. Histopathological examination revealed a tubulovillous adenoma. A tubulovillous adenoma developing at the augmented bladder is rare. To our knowledge, this is the second case in which a tubulovillous adenoma developed in an augmented bladder.