A 86-year-old woman presented with asymptomatic gross hematuria,and visited our hospital, and a vesicorectal fistula was suspected from a computed tomographic (CT) scan. She had a lower abdominal mass and urinary retention on arrival. Pclvic CT demonstrated intramural gas in the urinary bladder,which suggested a diagnosis of emphysematous cystitis. Cystoscopy demonstrated reddish mucosa and gas within the bladder wall. The gross hematuria was improved and the intramural gas disappeared on a CT scan after urinary drainage and antibiotic therapy. Although emphysematous cystitis is almost always cured with conservative therapy, an accurate diagonosis and prompt treatment are required because rarely emphysematous cystitis can result in rupture of the urinary bladder and lead to septic shock.