We describe the case of a 73-year-old woman was admitted to our hospital because of constant abdominal pain in her right upper quadrant and postprandial bloating and fullness for several months. On abdominal x-ray the extrahepatic bile ducts were positive for gas and on ultrasound a gallstone in the duodenum was suspected whereas the gallbladder was not detectable. An upper gastrointestinal endoscopy confirmed a large gallstone that was impacted in the duodenal bulb ("Bouveret's syndrome"). The gallstone was fragmented employing mechanical lithotripsy and removed. Duodenoscopy revealed a cholecystoduodenal fistula and a second gallstone in the gallbladder. The patient underwent open cholecystectomy with closure of the cholecystoduodenal fistula and made a full recovery. We conclude that in patients with upper abdominal pain and pneumobilia on x-ray the unusual complication of cholelithiasis with an impacted gallstone in the duodenal bulb should be suspected. In those rare cases of Bouveret's syndrome endoscopic removal of the gallstone should be attempted to minimize the necessary surgical procedure whenever possible.