The paper presents current diagnostic and therapeutic approach in parathyroid cancer. The suspicion of parathyroid cancer should be taken into account in patients with primary hyperparathyroidism symptoms (and elevated total and ionised calcium blood level and PTH blood level), present palpable cervical mass and enlarged cervical lymph nodes. Further diagnosis should be based on ultrasound of the neck (including power-Doppler ultrasound), subtraction 99mTc-MIBI and 123J scintigraphy, ultrasound-guided fine needle aspiration, and CT or MRI if necessary to assess the stage of the process. The elective surgical procedure should be primary 'en block' excision of the tumour with the unilateral thyroid lobe and the following loco-regional adjuvant radiotherapy. Patients who underwent surgical treatment due to parathyroid cancer require long-term follow-up as the risk of local recurrence or distant metastases (mostly into lungs or bones) remains high even many years after initial operation. Patients with dissemination usually suffer from severe hypercalcemia leading to death if untreated correctly. Thus, so crucial is effective treatment of hypercalcemia (diuresis, biphosphonates, calcitonine, oktreotide).