A 35-year-old female, who had undergone Caesarean sections in 2000 and 2001, presented with repeated candida vaginitis and cystitis. She reported that a piece of gauze was excreted through the urethra in 2005. The patient visited an outpatient clinic, but no foreign body was identified by cystoscopy. She again visited the clinic in 2012 complaining of miction pain, and a calcified mass was identified in the bladder. The patient was then referred to our hospital. During a transurethral operation, crushed stones, which included the gauze, were removed from the bladder. We concluded that remnant gauze left in the abdominal cavity during the previous pelvic surgery, had migrated into the bladder and formed a calcified mass.