This chapter describes the diagnosis, clinical features, and principles of management of primary hyperparathyroidism. The chapter focuses primarily on current management recommendations for patients with primary hyperparathyroidism, particularly for those with "asymptomatic" or mild disease. We also discuss the risks and benefits of parathyroidectomy for hyperparathyroidism and the various preoperative and intraoperative localization techniques currently in use to enable minimally invasive surgery. Lastly, we discuss the outcomes of medical and surgical therapy for this disease and the slightly different risk/benefit profile of parathyroidectomy in the reoperative setting. © 2010 Springer Science+Business Media, LLC.