A case of acute emphysematous cholecystitis was diagnosed in a female patient admitted for diabetic ketoacidosis. Clinical findings suggested empyema of the gallbladder. The plain film of the abdomen and abdominal ultrasonography performed immediately disclosed evidence of acute emphysematous cholecystitis. This diagnosis was confirmed by CT scan findings. This case and a review of the literature form the basis for a discussion of the main features of this disease.