We report a case of torsion of the gallbladder which is a rare disease and difficult to diagnose before operation. A 74-years-old woman was admitted to the hospital because of nausea, vomitting and abdominal pain in the right lower quadrant. Blood examination showed only the left shift in the white blood cell. Ultrasonography and computed tomography revealed a swollen gallbladder with no stone and with debris in the right lower quadrant. A crooked common bile duct without gallbladder was shown by drip infusion cholangiography. We suspected necrotic cholecystitis and operated. The gallbladder was twisted clockwise about 1 20 degrees. Then we gave a diagnosis of torsion of the gallbladder and performed cholecystectomy.