Kovi, J. and M. Y. Heshmat (Howard Univ. College of Medicine, Washington, D.C. 20001). Incidence of cancer in Negroes in Washington, D.C. and selected African cities. Am J Epidemiol 96: 401–413, 1972.—The results of a 5-year (1965–1969) survey of cancer among Negroes in 11 major hospitals in Washington, D.C., are reported. In males, the commonest sites of cancer, in order of decreasing frequency were prostate, lung, esophagus, and colon. In females, breast, cervix uteri, and colon were the most common sites. Among Negroes the overall incidence of malignant disease in Washington, D.C. was considerably higher than in Africa. The average annual incidence rate for males was 220.4/100,000 and for females 194.3. Incidence rates for both males and females reached a peak in the 70–79 age group, and then leveled off. Negroes in Washington, D.C., and in Alameda County, California, revealed a pattern of cancer risk for leading tumor sites, except cervix uteri, much closer to whites in Alameda County, California, than to Negroes in various parts of Africa, south of the Sahara. In fact, American Negroes had higher standardized incidence rates for cancer of the esophagus, stomach, pancreas, prostate and cervix uteri, but lower for breast, than Caucasians in Alameda County, California. Among Negroes in Africa, only the South African Bantu showed a trend in susceptibility to cancer comparable to American Negroes and whites. These findings emphasize the importance of environmental influences in the development of cancer in man.