Perfect localization of hyperactive parathyroid glands is useful to minimize operation time, incision and reduce patient morbidity. 52 patients with hyperparathyroidism were investigated, 14 with primary and 38 with secondary hyperparathyroidism following renal failure. Surgery has been done on 36 patients (14 with primary and 22 with secondary hyperparathyroidism). Sensitivity of 99mTc-tetrofosmin scintigraphy was estimated after surgical removal of Hyperfunctioning glands and compared with that of ultrasound and magnetic resonance imaging. The sensitivity of 99mTc-scintigraphy (79,5%) exceeded the sensitivity of ultrasound (68,2%) and magnetic resonance imaging (71,6%). Parathyroid hormone (P.T.H.) and calcium levels in serum were compared with positive 99mTc-tetrofosmin Scintigraphy. Results demonstrated correlation between positive 99mTc-tetrofosmin scintigraphy and parathyroid hormone levels with significant statistical difference of P < 0.001 and all patients with primary hyperparathyroidism with P.T.H. levels of 195 pg/ml or more were scintigraphically positives. All patients with secondary hyperparathyroidism with P.T.H. levels of 1200 or more were positives. No correlation was detected between calcium levels and positivity or negativity of scintigraphic results.