Primary hyperparathyroidism resulting in hypercalcemia is the most common presentation of parathyroid pathology and usually is related to a parathyroid adenoma and, less commonly, to hyperplasia. Imaging of the parathyroid glands focuses on the detection of adenomas in patients with primary hyperparathyroidism. The role of imaging (as well as the modality used) for preoperative localization of the parathyroid glands continues to be controversial. The embryology, anatomy, and physiology of the parathyroid glands are reviewed. The diagnostic utility of radiological imaging-including ultrasonography, CT, MR imaging, and nuclear scintigraphy-are discussed, particularly as it pertains to the evaluation of primary hyperparathyroidism.