Outpatient minimally invasive parathyroidectomy (MIP) employs (1) preoperative parathyroid localization with high quality sestamibi scans, (2) cervical block anesthesia, (3) limited exploration, and (4) the rapid intraoperative parathyroid hormone assay to confirm an adequate resection. The technical aspects of this procedure are described, and the results obtained in 255 patients who underwent MIP are compared with those of 401 patients who underwent conventional bilateral cervical exploration under general anesthesia. MIP and standard exploration were indistinguishable with regard to high cure and low complication rates. MIP, however, was superior with regard to operating time, length of hospital stay, patient comfort, and costs.