We describe a 77-year-old man with diabetes mellitus who developed a large gas-containing pyogenic liver abscess after admission. Mild elevation of serum biliary enzyme levels suggested probable biliary trouble on admission. Ultrasonography and computed tomography showed a large abscess of the liver with gas formation and the presence of gas within the lumina of the gallbladder and biliary tract when the patient had fever, leukocytosis and evidence of hepato-renal dysfunction. These findings suggest that the large liver abscess may have developed as a result of emphysematous cholecystitis.