A congenital duplication cyst, which presents with symptoms of gastric outlet obstruction, is an unusual disorder in humans and a rare condition in animals. A 5-day-old male Korean native cattle was presented with anorexia and no defecation. On exploratory laparotomy, an oval shaped mass (16 × 7 cm) was identified on the antimesenteric border of the proximal duodenum, with no communication between the intestinal lumen and the mass itself. Surgical correction for gastrointestinal tract patency was performed. The calf recovered well and was clinically normal three months after surgery. This case is the first report of a duodenal duplication cyst in a Korean native cattle.