Emphysematous cystitis is a rare infectious disease of the lower urinary tract of serious prognosis linked essentially to therapeutic failure in relation to the lack of knowledge of its pathophysiological mechanisms. We report a 69-year-old diabetic and hypertensive woman, hospitalized for alteration of the general condition, in a fever context. An ECBU is collected and returns positive to Escherichia coli ESBL. Diagnosis carried out on a Uro-CT scan, without IV, a bladder of airy contents, with the presence of air bubbles in the bladder wall. The evolution has been favorable under bi-antibiotic, with Cefoxitin and Metronidazole and urine drainage.