Emphysematous cystitis (EC) is a complicated lower urinary tract condition characterised by gas within the urinary bladder wall and lumen. It results from infection by gas‐producing microorganisms and has been reported in both diabetic and non‐diabetic dogs and cats with variable presentation. There are two case reports from the medical literature documenting subcutaneous extension of gas in people with EC, but this finding has never been reported in a veterinary patient. In this case, we identified abdominal wall emphysema as a complication of EC in a veterinary patient, secondary to recurrent urinary tract infection with Escherichia coli in a 10‐year‐old neutered female border collie with diabetes mellitus. Both radiography and ultrasonography were sensitive for the diagnosis of this condition and important in excluding retrograde extension of gas into the renal parenchyma.