Clinically significant hypoglycemia is an unusual complication of anorexia nervosa. We describe a 44-year-old woman with a 5-year history of anorexia nervosa who presented with hypoglycemic coma and eventually experienced sudden death. Biochemical studies showed suppressed levels of insulin, C peptide, and proinsulin during hypoglycemia; appropriate elevations of growth hormone and cortisol levels were observed, suggesting that the hypoglycemia was related to severe malnutrition. Nine previously reported cases of severe hypoglycemia in anorexia nervosa are reviewed (six of the patients involved also died). The presence of severe hypoglycemia in anorexia nervosa implies a grave prognosis and mandates aggressive medical and nutritional therapy to improve the chance of survival.