The preoperative localization and operative management of a high cervical intravagal parathyroid adenoma in a young woman with severe persistent primary hyperparathyroidism is presented. The etiology of persistent hyperparathyroidism is most frequently a missed adenoma that is often in an ectopic location; of these, undescended adenomas represent a small but important proportion. If clinical suspicion and preoperative localization procedures suggest an undescended gland, a direct surgical approach using a high cervical incision and a unilateral exploration is often successful.