Using technetium 99m diphosphonate as a bone scanning agent, 25 patients with Paget’s disease were studied with the rectilinear scanner and gamma camera. Paget’s bone had increased nuclide activity 5 minutes after intravenous administration when compared with normal bone. The bones involved with Paget’s disease had 3 to 5 times higher nuclide activity than the normal bone. Bone scans are useful to evaluate the extent of Paget’s disease in bones which are difficult to evaluate roentgenographically, such as the scapula. The lytic phase is quite different from the mixed phase of Paget’s disease, as compared with good quality fluorine 18 bone scans, technetium 99m diphosphonate scans appear to have comparable patterns of skeletal distribution of radionuclide, although the detail on the technetium 99m studies appears finer because of the improved statistics that come from administering a greater amount of radioactivity.