A 68-year-old man with a history of organic heart disease and marked weight loss was found to have apathetic thyrotoxicosis and hypercalcemia. Oral propranolol, 20.0 mg four times a day, provoked a gradual fall in serum calcium and alkaline phosphatase. It is concluded that relatively small doses of oral propranolol may be effective in the management of hypercalcemia accompanying thyrotoxicosis and that beta-blocking agents may not only inhibit the enhanced bone resorption caused by thyroid hormones but also block the stimulated osteoblastic activity.