Although many reports have demonstrated the sustained increase in bone mineral density (BMD) at trabecular sites in primary hyperparathyroidism (pHPT) after parathyroidectomy (PTX), there have been no data available on BMD changes over the long-term in pHPT patients with and without PTX in Japanese population. The present study was designed to investigate long-term BMD changes at both trabecular and cortical sites in Japanese pHPT patients with or without PTX.