Only a decade ago, it was anathema to most parathyroid surgeons not to perform bilateral exploration to evaluate all glands in each patient. Many things have changed in surgery during this time, however, and especially striking has been the trend toward less invasive procedures. In parathyroid surgery, several developments have allowed for a change in the traditional paradigm. One of these has been the advent of a more reliable preoperative imaging technique, sestamibi scanning. Another was the development of an intraoperative assay to confirm normalization of parathyroid hormone (PTH) after the removal of parathyroid glands. Others have used a hand-held gamma probe to help to localize the abnormal parathyroid glands, and some have applied videoendoscopic techniques to neck exploration. These factors have made more surgeons comfortable with unilateral exploration in most patients with primary hyperparathyroidism (HPT), which has allowed for smaller incisions, shorter operative times, and the use of monitored sedation instead of general anesthesia. The goal of this article is to review how each of these areas has evolved to bring about the current changes in the approach of many endocrine surgeons to the treatment of primary HPT.