This case report discusses a 77-year-old female patient who presented to an outpatient clinic with urinary symptoms and recurrent UTIs. Imaging revealed a foreign body, which was later confirmed as a retained intrauterine device (IUD) that had caused a vesicouterine fistula (VUF). The patient had a medical history of cervical cancer treated with radiation therapy, during which her IUD's string could not be located, leading to the decision to proceed with radiation therapy without removing the IUD. The patient opted to manage her condition medically rather than undergo surgical removal due to concerns about worsening the vesicouterine fistula. This case highlights the potential risks and complications of retained IUDs, and the importance of careful consideration and communication among clinical teams and patients when managing these situations.