The Authors report their experience on 136 patients with primary hyperparathyroidism. Nephrolitiasis was proven in 56 patients (41.3%), 20 patients (14.7%) were asyntomatic. Acute primary hyperparathyroidism was detected in 12 cases (8.8%). The preoperative localization of the diseased glands permits to minimize the procedure in terms of length and region of incision, extent of exploration and morbidity. 91.3% of the lesions were single adenoma, 7.3% double adenomas and 1.4% hyperplasia in MEN 1. The intraoperative PTH assay, performed in 90 patients (66.2%), showed a sensibility of 93.4%. Surgical treatment was successful in 93.4% of cases ( 127/136 patients), increasing to 97.0% (132/136 patients) if only recurrent hyperparathyroidism was considered, with no mortality and morbidity of 4.4%.