Background. Many elderly patients with primary hyperparathyroidism (1HPT), which increases in incidence with age and is frequently asymptomatic, are often not referred for surgery. However, the development of minimally invasive techniques has facilitated complex operations even in the elderly. Therefore, we sought to delineate the changes in the trends for surgical referral at our institution for patients over 70 years of age with 1HPT. Methods. From January 1990 to March 2004, 422 patients underwent surgery for 1HPT at our institution. Of these, 98 were 70 years or older. In 2001, we introduced minimally invasive radioguided parathyroidectomy (MIRP). Patients were then analyzed based upon the availability of this technology (pre-MIRP era 1990-2000, and MIRP era 2001-2004). Results. In the MIRP era, more elderly patients were referred for surgery when compared to the pre-MIRP era (30% versus 18%, P = 0.001). On average, 18 elderly patients/year had parathyroid surgery in the MIRP era compared to only 4 elderly patients/year pre-MIRP, representing a 4.5-fold increase. Furthermore, there were significantly more patients undergoing parathyroidectomy who were asymptomatic from 1HPT during the MIRP era (14% versus 2%, P < 0.001). Importantly, patients who underwent surgery in the MIRP era had a higher cure rate, lower complication rate, and shorter hospital stay. Conclusions. Since the introduction of MIRP at our institution, there has been an increase in the number of elderly patients with 1HPT referred for surgery as well as the proportion with only mild disease. Furthermore, there have been improvements in elderly patient outcomes during this time. MIRP is one of several factors that have led to an increase in elderly patients undergoing surgery for 1HPT. © 2005 Elsevier Inc. All rights reserved.