The authors conducted a survival analysis to determine the effect of poverty on mortality in a national sample of blacks and whites, 25 to 74 years of age (the first National Health and Nutrition Examination Survey (NHANES-1) and NHANES-1 Epidemiologic Follow up Study). They estimated the proportion of mortality associated with poverty during 1971-1984 and in 1991 by calculating population attributable risk and assessed confounding by major known risk factors (e.g., smoking, cholesterol levels, and physical inactivity). In 1973, 6.0 percent of U.S. mortality among black and white persons 25 to 74 years of age was attributable to poverty; in 1991, the proportion was 5.9 percent. In 1991, rates of mortality attributable to poverty were lowest for white women, 2.2 times as high for white men, 8.6 times as high for black men, and 3.6 times as high for black women. Adjustment for all these potential confounders combined had little effect on the hazard ratio among men, but reduced the effect of poverty on mortality among women by 42 percent. The proportion of mortality attributable to poverty among U.S. black and white adults has changed only minimally in recent decades. The effect of poverty on mortality must be largely explained by conditions other than commonly recognized risk factors.