A case of small bowel obstruction in a 75-year-old female patient is reported. Due to Bouveret’s syndrome we found a huge gallstone in the duodenum, which could not be retrieved during the attempt of endoscopic treatment. Before the planned surgical treatment the stone moved to the small bowel and caused biliary obstruction. During surgery the gallstone and post-inflammatory changed gallbladder were removed. The cholecystoduodenal fistula was closed. The postoperative course was uneventful and the patient is currently in a good condition.