Purpose: A 71-year-old female presented with a 3 year history of early satiety, anorexia, abdominal distention and weight loss of 22 pounds. Past medical history was unremarkable. Physical exam was significant for a non-tender 5 cm epigastric mass. Laboratory findings included normal blood counts, tumor markers, liver biochemistries and pancreatic enzymes. CT scan of the abdomen revealed a 9.3 x 5.2 x 9.5 cm well circumscribed cystic mass with thickened walls arising above the gastro-duodenal junction. Upper endoscopy revealed a 5 cm mass protruding into the gastric antrum, covered by intact mucosa and draining whitish fluid. Histopathology of mucosa showed chronic gastritis without Helicobacter pylori. An exploratory laparotomy revealed a cystic mass attached to the anterior part of the gastric antrum, arising 3.5 cm above the pylorus. The lesion was resected with a margin of normal stomach, and the gastric defect was closed. Macroscopic examination revealed a 12 x 10 x 4 cm saccular mass, with a nodular external layer and foul smelling content. Microscopic examination revealed gastric inner mucosal lining, thickened muscularis propia and outer serosal layer. No malignant cells were observed. All these features were consistent with a gastric duplication cyst (GDC). Patient remained asymptomatic at 3 months follow-up. GDC represents an uncommon developmental malformation of the gastrointestinal tract. They account for 9% of gastrointestinal duplication cysts and are nearly twice as common in females as male. About 67% of patients have presented within the first year of life, but diagnosis has been made as late as in a 67-year-old patient. Approximately 150 cases have been reported in literature to date with our case representing the oldest patient described. Clinical presentations range from asymptomatic to acute abdomen, pancreatitis, upper gastrointestinal bleeding and gastric outlet obstruction. Most commonly other nonspecific symptoms are described such as nausea, vomiting, pain, weight loss, bloating, fever and epigastric mass. Malignant transformation of the cyst can occur, but its malignant potential is still unclear. Despite the recent advances in diagnostic imaging, preoperative diagnosis of GDC in adults remains difficult and definitive diagnosis requires surgical findings together with histopathological examination. The treatment of GDC is by open resection, but other approaches such as laparoscopic and endoscopic resection have been described. Though rare, gastric duplication cyst should be part of the differential diagnosis in patients with gastric tumors.