The authors report a case of sudden death in a 23-year-old woman in whom autopsy by the medical examiner revealed hypothalamic sarcoidosis. The decedent had experienced 6 months of amenorrhea and a 50-pound weight gain. She sought medical attention when she experienced headache, and after imaging and laboratory studies, she was suspected of having neurosarcoidosis. She appeared to respond well to corticosteroid therapy. However, 6 weeks after the beginning of therapy, she was found dead on the floor of her residence. Autopsy showed extensive granulomatous inflammation of the hypothalamus and adjacent structures. Previously reported cases of hypothalamic sarcoidosis are reviewed. A hypothesis for the mechanism of sudden death is presented.