Spontaneous urinary bladder perforation is a very rare disease. The main cause of urinary perforation, indeed, is a damage to the urinary bladder wall by blunt or penetrating trauma. There are only few idiopathic spontaneous rupture of urinary bladder (ISRUB) cases reported in the literature. Pre-operative diagnosis is very difficult due to similar symptoms, laboratory and imaging findings of a gastrointestinal perforation that is usually excluded intraoperatively. Herein we report a case of a 91-year-old man presented to the emergency department with a spontaneous bladder perforation mimicking an ileal perforation.