An 81-year-old woman presented with left hypochondrial pain and vomiting. CT showed incarceration of the entire stomach in the left pleural cavity with esophageal hiatus hernia with mesenteroaxial gastric volvulus. We diagnosed upside down stomach. Upper gastrointestinal endoscopy showed no impairment of blood supply to the gastric mucosa and she had cardiac complications, so nasogastric tube insertion and conservative management were performed. Two weeks later, her upside down stomach had resolved and only hiatus hernia was seen. We then performed a Nissen operation.