CARCINOMA of the parathyroid gland is a rare cause of primary hyperparathyroidism, accounting for approximately 3–4% of patients with hypercalcemia and elevated parathyroid hormone levels (1, 2). In 1969, Holmes et al. (3) reviewed the data on 46 patients with parathyroid carcinoma published since the original description of the disease in 1938. The subjects of that report had, in general, marked and symptomatic hypercalcemia as well as the frequent presence of both skeletal and renal complications of hyperparathyroidism. These observations suggested that malignant parathyroid disease usually presented somewhat differently than the much more common benign form of primary hyperparathyroidism. Since the report of Holmes et al. (3) there have been additional clinical descriptions of parathyroid carcinoma but no further comprehensive reviews in English. Over this same period of time, surveys of benign primary hyperparathyroidism have documented a rather dramatic change in its incidence and clinical presentation (4–9). Has the clinical profile of parathyroid carcinoma also changed? This question, as well as our involvement in the care of five patients with parathyroid carcinoma, has prompted us to review the more recent history of this tumor.