Disturbances of calcium metabolism such as hypercalcemia or/and hypercalciuria in the course of sarcoidosis can be a cause of renal failure in some patients. Life threatening hypercalcemia in sarcoidosis patients is not very frequent. Severe hypercalcemia leading to renal insufficiency is a very rare condition. We present a case of 53-year old man who was admitted to Department of Lung Diseases because of hypercalcemic syndrome and renal failure, and in whom diagnosis of sarcoidosis was made. He was successfully treated with systemic corticosteroids. In this article we present physiological mechanism of hypercalcemia in sarcoidosis patients, mechanism of renal damage and management of these difficult problems.