There have been few prospective studies of the epidemiology of cardiovascular disease in women, especially black women. The authors report the 20-year mortality experience of 391 black and 549 white women aged 40-64 years recruited in 1960-1961 into the Evans County Cardiovascular Study. The vital status of 98.9% of the white women and 96.2% of the black women had been determined as of May 1, 1980. Using Cox' proportional hazards model, the authors estimated that black women had a 70% excess risk of cardiovascular disease mortality compared with white women, unadjusted for any risk factors. At entry, black women had higher systolic blood pressure, higher Quetelet index, lower serum cholesterol, lower social status, and similar age distribution and prevalence of cigarette smoking compared with white women. Cardiovascular disease mortality was significantly associated with systolic pressure in all women, serum cholesterol in white women, and Quetelet index in low social status white women. Adjustment for cardiovascular disease risk factors and social status explained most of the difference in cardiovascular disease mortality between blacks and whites.