Cholecystitis can result in complications if not completely treated. These include gallbladder empyema, perforation and cholecystoenteric fistula.We report the first incidence of cholecystitis resulting in a gallstone fistula with a gastric duplication cyst. A 71 year old patient presented with generalised peritonism that was worst in the epigastric area. Computer tomography (CT) revealed a perforated necrotic gallbladder. Emergency laparotomy, cholecystectomy, partial gastrectomy and Roux-en-Y reconstruction was required. The patient made a slow but full recovery.Pathology results revealed that chronic cholecystitis had resulted in a fistula with a duplication cyst overlying the greater curve of the stomach. Several one centimeter gallstones were found within the cyst cavity.