We report the first autopsy case of fatal gastric dilatation without rupture. A 31-year-old woman who lived alone was found dead in her living room. Despite being very thin, she showed marked abdominal distention. Autopsy and histological findings revealed that a severely distended stomach, of which walls notably thin and displayed transmural necrosis, occupied the entire abdominal cavity. Severe congestion was observed in the intestine and cecum. Theses findings suggest that bulimia nervosa together with anorexia nervosa resulted in rapid dilation of the stomach. We conclude that the cause of death was acute circulatory failure from hypovolemic shock that occurred following compression of the inferior vena cava and superior mesenteric vein, and by loss of circulatory volume to the third space.