More than 95% of patients with Primary Hyperparathyroidism (PHPT) are treated successfully at the initial operation when the operation is done by an experienced surgeon, but the success rate is considerably lower when done by an unexperienced surgeon. The approach to patients with persistent and recurrent PHPT is to confirm the diagnosis and to use precise localization procedures done by expert radiologists. Reexploration after one or more previously failed parathyroid operations is unfortunately associated with a higher morbidity and a lower success rate. Improved pre- and intraoperative testing during the last decade has improved the results of reoperation and allowed more focused approaches. Preoperatively, we recommend a combination of sestamibi scanning, ultrasound, and MRI scanning. Highly selective venous sampling for iPTH is recommended for patients with recurrent or persistent PHPT when the non-invasive studies are negative, equivocal, or discordant. Several factors such as age of the patient, severity of symptoms, comorbidity, and the results of localization studies, should all be considered in the management of these patients although we believe that reoperation is indicated for most of these patients. Today successful reoperations can be done in more than 90% of patients with a relatively low morbidity rate.