Massive gastric dilatation with necrosis and rupture is a very rare event. Here we describe the case of a 13-year-old girl with acute gastric dilatation, infarction, necrosis and perforation. It began with acute abdominal pain, but an absence of vomiting after eating a heavy meal. Laparotomy showed massive gastric dilatation with infarction and perforation. Early diagnosis is essential to reduce morbidity and mortality, and therefore treatment must be started promptly.