A 30-year-old normocalcemic man with hypopituitarism, hypogonadism, diabetes mellitus, and secondary hemochromatosis due to multiple blood transfusions was admitted because of adrenal crisis. After intravenous administration of saline and cortisol, the corrected serum level of calcium decreased to 7.3 mg/dl. This osteoporotic patient had been prescribed alendronate for radial bone fracture. Since the increase in intact PTH (68 pg/ml) was impaired compared to that seen in hypocalcemic patients with secondary hyperparathyroidism, we presume that the patient has had latent hypoparathyroidism, which was unmasked by the administration of glucocorticoid and bisphosphonate. With a supplemented dose of 1alpha-OHD3, the patient has been eucalcemic.