Kuller, L. H. (Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, Md. 21205), A. Bolker, M. S. Saslaw, B. L Paegel, C. Sisk, N. Borhani, J. A. Wray, H. Anderson, D. Peterson, W. Winkelstein, Jr., J. Cassel, P. Spiers, A. G. Robinson, H. Curry, A. M. Lilienfeld and R. Seltser. Nationwide cerebrovascular disease mortality study. III. Accuracy of the clinical diagnosis of cerebrovascular disease. Amer. J. Epid., 1969, 90; 556–566—The large differences in cerebrovascular disease mortality among geographic areas of the United States may be due to differences in the accuracy of the diagnosis of stroke. The accuracy of the diagnosis of stroke among areas of the United States with high, intermediate or low cerebrovascular mortality rates was studied by reviewing clinical records for every death included in the nationwide cerebrovascular disease mortality study. The frequency of most symptoms of stroke was similar among the areas. For stroke deaths in a hospital, hemiplegia was listed on 55% of the hospital charts and coma on 657%. Approximately 85% of the hospital stroke deaths could be validated by either an autopsy, arteriogram, hemorrhagic spinal fluid, hemiplegia or coma on admission. There were no differences among the high, low and intermediate cerebrovascular disease mortality areas. When stroke was the underlying cause on the death certificate, 69.5% of the clinical records from hospitals, physicians or medical examiners reported coma; 49.1%, hemiplegia; 25.8%, an autopsy of the brain; 33.4%, a spinal puncture; 7.9%, an arteriogram; and 2.4%, a craniotomy. Differences in the accuracy of the diagnosis of stroke apparently did not account for geographic variations in cerebrovascular disease mortality among areas of the United States.