There is little debate about the primacy of surgery in the management of symptomatic or complicated primary hyperparathyroidism. Rather, the question has been what to do about the many patients with nonclassical disease. Recent prospective data have confirmed that patients with asymptomatic primary hyperparathyroidism who are not surgical candidates for parathyroidectomy appear to do well when they are managed conservatively. On average, these patients remain stable, with little progression to the more serious manifestations of hyperparathyroidism over 10 years. It would seem, therefore, that the overall population of older patients with mild asymptomatic primary hyperparathyroidism can be safely followed without intervention. A certain proportion of cases do progress, however, so surveillance is necessary. Individual patients can have worsening hypercalcemia or hypercalciuria, and in a small percentage of patients, bone density may decrease over time. In most patients, deferral of surgery is not a one-time decision, but rather one that is reviewed and reconsidered in conjunction with meticulous monitoring.