We report here a case of torsion of the gallbladder in a 73-year-old woman. The patient was admitted to our hospital with right hypochondralgia. Ultrasonography and computed tomography demonstrated a distended gallbladder, with a multilayered wall, which contained no stones. Since the symptoms did not respond to antibiotics, laparotomy was performed. The gallbladder was found to be twisted around its pedicle and to be gangrenous. Cholecystectomy was performed, and the patient had an uneventful postoperative course. We also reviewed 245 cases reported in the Japanese literature. The clinical features of gallbladder torsion, which include low frequency of fever and jaundice, poor response to antibiotic therapy, and acute onset of abdominal pain, may be helpful in the differential diagnosis from acute cholecystitis. Moreover, a highly suggestive sign of gallbladder torsion observed by ultrasonography or computed tomography is a markedly enlarged "floating" gallbladder with a continuous hypoechoic line indicating edematous change in the wall.