From 1987 to 2008, 226 patients were operated on for primary hyperparathyroidism (pHPT). In 17 (men and women, aged 2171 years) of them, parathyroid carcinoma (PC) was verified by histologic analysis. Mixed pHPT form was noted in 12 patients, visceropathic one in 4, and asymptomatic in 1. Hypercalcemia was revealed in 14 of 17 patients, and elevation of parathyroid hormone (PTH) level (4261160 pg/ml) in 12. In 5 patients operated on before 1990, serum PTH level was indefinable. Neck palpation revealed tumor-like neoplasm in 14 patients. US neck scan showed tumor-like neoplasms in 10 patients. CT demonstrated one tumor in anterosuperior mediastinum, the second one behind trachea (at the level of CVI). Three patients underwent only tumor resection because thyroid invasion wasnt suspected by that time. In addition to PC resection, one patient underwent thyroid lobe resection, 4 hemithyroidectomy, 3 subtotal thyroidectomy, and 5 total thyroidectomy. In one patient, sternotomy allowed to reveal a tumor with cystic degeneration in the right superior thymic limb. It was woody-dense and intimately connected with a sternoclavicular joint, subclavian artery, and brachiocephalic vein. Thymectomy and subtotal thyroid resection were performed. In postoperative period, in 16 of 17 patients, clinical manifestations of differently pronounced hypoparathyroidism developed and was confirmed by laboratory data. One patient died after operation due to pancreanecrosis. Remote outcome (later than 6 months 15 years after operation) was studied in 11 patients. By the time of examination, all these patients were alive and no signs of tumor recurrence or regional and remote metastases were revealed. When suspecting PC, careful following ablation technique during surgery is needed which can help avoiding capsule damage especially as parathyroid tissue is markedly capable of implantation. After urgent histologic investigation and diagnosis verification, its necessary to be sure that operation was radical enough. As a rule, resection of PC is associated with simultaneous removal of adjusting thyroid lobe. Revision of ways of the regional metastatic spreading is obligatory as well as lymphadenectomy, if necessary.