Recent advances in the techniques of preoperative parathyroid localization include ultrasonography, computed tomography, thallium-technetium subtraction scanning, magnetic resonance imaging, digital subtraction angiography with selective venous catheterization for PTH measurement, and ultrasound or CT-guided needle aspiration biopsy for cytological examination or PTH assay. These techniques are helpful for patients with hyperparathyroidism undergoing the initial operation, and essential for patients with persistent or recurrent hyperparathyroidism undergoing reoperation. Noninvasive procedures should be performed first, and the combination of any two positive studies localizes the tumor with near certainty. Invasive procedures have a higher risk of complications and are recommended only in selected patients before reoperation.