Intra-abdominal retained surgical sponge is an uncommon surgical error. Herein, we report a 92-year-old woman who was brought to the emergency room for acute urinary retention. She had a history of vaginal hysterectomy for uterine prolapse 18 years previously, performed at our hospital. Retained surgical sponge in the pelvic cavity was suspected by abdominal computed tomography. The surgical gauze was removed by laparotomy excision and the final diagnosis was gossypiboma.