A male, 9-year-old Bengal tiger (Panthera tigris tigris) with low serum T3 and T4 concentration died one day after recovering from anesthesia for routine health evaluations. Post-mortem radiographic findings revealed a distended stomach and loops of bowel in the thoracic cavity. At necropsy, severe displacement of abdominal viscera into the thoracic cavity through the esophageal hiatus was accompanied by rupture of the diaphragm, volvulus of abdominal viscera, strangulation of the intestines, and collapse of the lung. Microscopically, there were marked myodegeneration and myonecrosis of the diaphragm and varying degrees of congestion in the displaced organs. The thyroid had variably sized and shaped thyroid follicles with slight lymphocytic infiltration in the interstitium. The present case suggests that a hiatus hernia may be one of the life-threatening post-anesthesia complications in tigers with hypothyroidism.