Gallstone obstruction of the duodenum (Bouveret's syndrome) is a very rare complication of biliary calculosis. A great biliary calculus with long-term persistence causes cholecystoduodenal fistula and after passing through this fistula into duodenum, subsequent duodenal obstruction develops. The authors present a 73-years-old woman with Bouveret's syndrome. She was admitted to the Institute of digestive diseases with clinical signs of high intestinal obstruction. Preoperative radiographic examination detected gallstone obturation of the duodenum. At operation, two large gallstones were extracted from the duodenum, a thickened gallbladder was removed and duodenal suture was done. Post-operative course was delayed, due to respiratory complications and the patient went home on the 37th day after the operation in good condition.