The role of parathyroid localization is as a preoperative localization procedure. This is becoming increasingly important with the trend towards limited surgical approaches. Although there are a variety of methods used to identify the site of parathyroid adenomas, 99mTc sestamibi is at present the agent of choice. Debate continues as to whether imaging is best performed using a subtraction technique or delayed imaging/dual phase technique. There is also discussion as to which collimator to use and whether surgery should be directed by the combined use of ultrasound and radionuclide imaging. These areas are discussed within this review. The technique of choice is a subtraction 99mTc sestamibi scan of the neck using a pinhole collimator. This should be combined with a mediastinal view using a parallel hole collimator. There is sufficient evidence to suggest that combining subtraction imaging with high resolution ultrasound will improve the sensitivity and give greater information to the surgeon.