We present a case of spontaneous bladder rupture in a 49-year-old woman who had undergone radical hysterectomy and pelvic radiation therapy 10 years ago. Her chief complaint was acute abdominal pain. Abdominal computed tomography revealed ascites, which contained higher levels of creatinine, indicating intraperitoneal urinary extravasation. Following conservative therapy with an indwelling catheter, intermittent self-catheterization was introduced to prevent recurrence of the rupture. Perforation of the urinary bladder should be considered in patients with acute abdomen, particularly in those with previous histories of pelvic surgical or radiation therapy.