In a study designed to assess the potential value of radionuclide aortography in diagnosis of aortic and anastomotic aneurysms, 43 patients were examined. Radionuclide studies correctly identified 26 of 28 aortic aneurysms while physical examination identified 26 of 28, and lateral plain film roentgenograms showed 23 of 28. Three of five anastomotic aneurysms were demonstrated by the radionuclide technique. The radionuclide study was helpful in finding three previously unsuspected aneurysms and in excluding four abdominal and three thoracic masses from consideration as aneurysms. Clearly, this noninvasive technique has utility in lending objectivity to evaluation of patients with arterial aneurysm disease.