In this study we try to clear the prevalance of age and sex and clinical and radiographic manifestations of primary hyperparathyroidism. In this duration 47 patients with primary hyperparathyroidism that bed in two important hospitals in Tehran were studied.The ratio between women to men was 7 to 1 and most prevalance of disease were in fouyth decade. The pain boon was the cheif complain of patients and osteopenia was the most radiographic findings.In addition a case of primary hyperparathyroidism with mandibular and other bone involvement was reported.