A 17-year-old woman manifested fever, abdominal pain, headache, and hypertension caused by a solitary, benign pheochromocytoma. She also had hypercalcemia and elevated plasma immunoreactive calcitonin levels. After removal of the pheochromocytoma, calcium and calcitonin levels returned to normal. Studies of peripheral and tumor venous blood showed no excess or ectopic parathyroid hormone secretion, but the tumor contained and secreted calcitonin. Sporadic pheochromocytoma may secrete calcitonin and cause hypercalcemia by non-parathyroid hormone-mediated mechanisms. The potential is clearly present for confusion with multiple endocrine neoplasia, type 2 (medullary thyroid carcinoma, pheochromocytoma, and primary hyperparathyroidism).