Parathyroidectomy (PTX) is the only option available for the cure of hyperparathyroidism (HPT). After PTX, biochemical bone markers rapidly decrease and return to normal. Bone resorption markers decrease faster than bone formation markers. Increase in bone mineral density (BMD) by PTX is explained by time lag between changes in bone resorption and bone formation markers. Several lines of evidence indicate that PTX preferentially leads to increase in trabecular BMD in primary HPT patients. However, a considerable increase in BMD is obtained after PTX even in asymptomatic patients. Recent studies suggest that PTX reduces the risk of fracture in primary HPT (PHPT) patients. Changes in bone structures after PTX remain to be elucidated.