We herein describe a case of acute emphysematous cholecystitis in which the patient presented with symptoms of ileus. The patient was a 72-year-old man with no history of diabetes mellitus. He presented with epigastric pain, vomiting, and low-grade fever. Plain abdominal radiography showed some intestinal gas and niveau, and he was admitted to our hospital with a diagnosis of ileus. The next day, the abdominal pain increased and was accompanied by muscular defense. Plain radiography and computed tomography of the abdomen were carried out, and an emergency laparotomy was performed under a diagnosis of panperitonitis due to a perforation of the gallbladder caused by acute emphysematous cholecystitis. The patient made favorable progress after the operation and was discharged on postoperative day 14. Percutaneous transhepatic gallbladder drainage has been increasingly performed for the treatment of acute emphysematous cholecystitis. but when a perforation of the gallbladder is suspected, a laparotomy first should be considered.