Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia. An autonomous overproduction of parathyroid hormone leading to hypercalcemia, which is not downregulated by the calcium-sensing receptor, is the pathophysiological basis of the disease. The classical manifestations of PHPT include a generalized bone disease, kidney stones, and nephrocalcinosis, gastrointestinal, cardiovascular, neuromuscular and neuropsychiatric symptoms. Recently, the clinical presentation of PHPT, however, has changed in Western countries, it occurs oligo-asymptomatic in up to 80 %. Clinical examination, laboratory, and imaging techniques for the characterization of the disease and the localization include the diagnostic procedure. If possible, parathyroidectomy is the treatment of choice for clinically overt PHPT, for asymptomatic PHPT guidelines were developed in order to decide in individual cases between surgical and conservative approach; this consists of monitoring, adequate calcium and vitamin D intake, as well as hydration. Medical therapy includes bisphosphonates and calcimimetics.