Gallstone ileus is a rare but important cause of small bowel obstruction in the geriatric population. A 65-year-old man with a twenty year history of cholecystolithiasis was admitted to our hospital with abdominal pain and vomiting. Physical exams showed abdominal defence and rebound tenderness. A plain abdominal X-ray suggested a small bowel obstruction and pneumobilia. CT scan revealed a 2.5-cm gallstone at the jejunum and air in the biliary tree. The patient underwent a emergency laparotomy based on a diagnosis of panperitonitis with a perforation associated with gallstone ileus. Operative findings revealed a jejunal perforation and a impacted stone on the anal side of perforation. Enterolithotomy and jejunal resection were performed with cholecystectomy and repairment of the cholecystoduodenal fistula.