Background. Parathyroid carcinoma is the least frequent malignancy among endocrine tumors. In the most reported series of patients with primary hyperparathyroidism the incidence of carcinoma is less than 1%. Recognition by a surgeon that the parathyroid tumor is malignant, and the performance of an adequate en bloc removal of primary lesion, with histologic diagnosis offer the best treatment of a patient with this unusual malignancy. Case report. We reported a 30-year-old patient with parathyroid carcinoma, primary hyperparathyroidism, and recurrent nephrocalcinosis. Marked hypercalcemia, low serum phosphorus, and substantial elevation of serum parathyroid hormone indicated a diagnosis of primary hiperparathyroidism. General symptoms were anorexia, muscle weakness, back pain and depression. Ultrasonography done before the surgery revealed a 2 cm upper left parathyroid gland with solid and cystic areas. The neck exploration was done with en block resection of the tumor. A histopathological evaluation confirmed the diagnosis of parathyroid carcinoma. Over more than a three-year-follow-up, the patient had no evidence of the disease recurrence and his serum PTH and calcium levels remained within the normal. Conclusion. Parathyroid carcinoma is a rare cause of primary hyperparathyroidism. Preoperative diagnosis remains a challenge. Radical en bloc resection of the tumor is the treatment of choice for this malignancy.