A 95-year-old man was admitted to the hospital due to a sudden onset of nausea and abdominal pain. Physical examination revealed abdominal distension with mild epigastric tenderness. Computed tomography showed a grossly distended stomach with displacement of the antrum above the esophago-gastric junction, and he was diagnosed with acute mesentero-axial gastric volvulus. We attempted urgent reduction using conventional endoscopy, but failed. He and his family did not want surgery because of his extreme advanced age, and a nasogastric tube was inserted to his stomach for decompression expecting a natural reduction. On the next day, however, it was not improved, so endoscopic reduction was tried again by a balloon-assisted endoscope without an overtube under X-ray fluoroscopy. When the scope reached the descending portion of the duodenum, the balloon on the scope tip was inflated, and the stomach position was reduced by pulling back the scope with twisting to the right. He was discharged from the hospital without any complication, and no recurrence has been observed for 12 months thereafter. We suggest a balloon-assisted endoscope as a useful tool for reduction of gastric volvulus especially in cases of reduction failure by a conventional one.