Hypercalcemia is a common clinical problem. Primary hyperparathyroidism and malignancy are the most common causes of hypercalcemia, accounting for more than 90% of cases. Other causes of hypercalcemia occur less frequently but are important to consider in clinical situations (ie, vitamin D intoxication, chronic granulomatous disorders, hyperthyroidism, acromegaly, pheochromocytoma, adrenal insufficiency, immobilization, parenteral nutrition, milk alkali syndrome, and some medication including thiazide diuretics, lithium, teriparatide, excessive vitamin A, and theophylline). Therefore, these patients require a specialized service before starting treatment.