Worth, R. M., H. Kato, G. G. Rhoads, A. Kagan and S. L. Syme (School of Public Health.U. of California. Berkeley. CA 94720). Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: Mortality. Am J Epidemiol 102:481–490. 1975. Stroke, coronary heart disease (CHD) and total mortality are evaluated from death certificates in enumerated cohorts of 45–64-year-old Japanese men in Hiroshima and Nagasaki (1965–1970), in Honolulu (1966–1970), and in the San Francisco area (1968–1972). Total mortality is highest in Japan with no consistent differences between Japanese Americans in Honolulu and San Francisco. Age-specific CHD death rates are markedly lower in all three Japanese groups than in American whites. The CHD rates are consistently and significantly lower in Japan than in American Japanese. Stroke death rates for American Japanese men appear equivalent to figures for US white men of the same age, but are significantly lower than in the Japan cohort for the 60–64-year-old group.The number of stroke deaths below that age are too few as yet for analysis. Validation ofmortality ascertainment and of the accuracy of death certification has been carried out in Japan and in Hawaii. The international differences in mortality do not appear to be dueto certification or other methodologic artifact.