Gallbladder perforation is an almost exclusive complication of cholecystitis, which accompanies severe inflammation of the gallbladder with or without cholelithiasis. Whether it is of a calculous or acalculous origin, gallbladder perforation, as a complication of acute cholecystitis, has common symptoms, signs, laboratory data, radiological findings and treatment modalities. Even though many reports of gallbladder perforation have been published, there are few reports of gallbladder perforation without any clinical and radiological indications. We experienced a case of a 70-year-old woman with acute abdomen, which was found to be peritonitis caused by spontaneous gallbladder perforation that was devoid of clues suggesting this condition. Although rare and unusual, this case shows that this disorder should be considered in elderly patients presenting with peritonitis with an unknown etiology.