Gastric volvulus in conjunction with diaphragmatic hernia is an uncommon but life-threatening presentation that is generally in association with hiatal hernia or diaphragmatic injuries. Diaphragmatic hernia with gastric volvulus can occur many years after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy despite initial diaphragm intactness, and should be suspected in this patient population when they present with upper gastrointestinal obstruction. An acute episode of gastric volvulus can have a mortality of 30% to 50%, hence the importance of early diagnosis and treatment. Surgical management remains the treatment of choice and can be an emergency in obstructive cases. We report the case of a 68-year-old woman presenting with signs and symptoms of acute upper gastrointestinal obstruction. Three years ago, the patient had undergone debulking surgery and hyperthermic intraperitoneal chemotherapy for peritoneal carcinomatosis secondary to advanced ovarian cancer. A diagnosis of gastric volvulus was established. The pylorus was seen near the cardia on gastroscopy, and barium swallow showed stomach upside down and with a mirror image of normal anatomy suggestive of gastric volvulus. We opted for urgent laparotomy that revealed the presence of a rotated stomach adherent to the spleen and left diaphragm. After reduction, a diaphragmatic defect that was missed on the computed tomography scan was discovered and repaired, and the patient recovered uneventfully.