Because of an appropriate gamma-energy and relatively short half-life of 6 hours, technitium-99m-pertechetate (99mTc) has been claimed to be superior or equal to iodine-131-iodide (131I) in scanning of the thyroid gland. The present communication reports the results of our clinical study on advantages of 99mTc over 131I for thyroid scanning in the subjects with normal or abnormal uptake values and with“cold”nodules. The material consisted of 33 patients with various thyroid function states. We performed the 24-hour uptake study of Na131I following the oral administration of 40$mu$Ci“atomic cocktail”. Then a scan was carried out using Scintimat 2F scanner with the window set for 364 KeV and a 31-hole collimator. The 131I-scan was followed by 99mTc-scan 15 minutes after intravenous injection of 2 mCi of Na99mTcO4. The window was set at 140 KeV and a 396-hole collimator was used. The mean and standard deviation of Q values for the 99mTc scanning was 14.5$pm$5.4 with the range from 8 to 27 and for the 131I scanning 5.3$pm$0.95 and from 4 to 8.5. This indicates that the scan quality was nearly 3 times superior when 99mTc was used. Viewing of color scans revealed obviously improvement in the quality of the scan image in terms of much more orderly color-dot distributions and sharper profile.