The aim of the study was to evaluate the clinical, surgical and pathological prognostic factors of postoperative disease progression in parathyroid cancer patients.Material and methods. This is a retrospective study of 19 patients operated on between 1983 and 2007 for parathyroid cancer at the Department of General Surgery of the Silesian Medical University constituting 4.6% of the total 416 patients operated on during that time for primary hyperparathyroidism.Results. The study is based on a group of 7 (27%) men and 12 (63%) women aged 27 - 77 (av. 56). On admission, serum calcium levels exceeding 3.5 mmol/L were observed in 11 (58%) patients with parathyroid cancer and in 4 (1%) of the 397 patients with benign changes. Serum parathormone (PTH) levels higher than 450 pg/ml were found in 9 (47.4%) and 11 (2.8%) patients, respectively. Whenever parathyroid cancer was suspected, an en block resection of the parathyroid tumor including a wide margin of adjacent tissue was performed. Ipsilateral thyroid lobectomy was performed on 14 patients but in 5 cases total thyreoidectomy was required. 14 (73.7%) patients underwent either ipsilateral (11x) or bilateral (3x) lymphadenectomy. Within the group of 19 patients a total of 41 operations were required, including 4 operations in other medical centers. Three patients underwent adjuvant radiation therapy. The cumulative postoperative 5-, 10- and 15-year survival rate for the 19 parathyroid cancer patients was 95%, 82.5% and 62% respectively. Local and/or regional recurrences as well as remote metastases were found in 7 and 6 patients, respectively. Of the former group six patients are still alive after 3, 7, 9, 10, and - in two cases - 12 years (the 7th patient died 14 years after the first operation). Of the latter group three patients died of cancer dissemination 5, 7 and 8 years after the initial operation, but three others are still alive after 7, 10 and 14 years while still displaying the disease symptoms. Six patients, all of whom underwent one-stage resection of parathyroid glands and both ipsilateral thyroid lobectomy and lymphadenectomy, are still alive 8, 10, 11, 13, 14 and 21 years after with no evidence of the disease.Conclusions. 1. Parathyroid cancer should always be suspected while dealing with primary hyperparathyroidism in patients with significantly elevated serum calcium and PTH levels. 2. Ipsilateral lymphadenectomy is advocated for parathyroid cancer patients already during the initial operation. 3. In order to avoid parathyroid cancer relapse even many years after the surgery, periodic checks are recommended for the rest of the patients' lives.