The authors analyze 100-year U.S. national income-inequality trends in relation to trends in mortality rates by age group and for heart disease, cerebrovascular disease, infants, suicide and homicide. The authors also review U.S. regional trends in mortality from all causes and from ischemic heart disease; stroke; lung, breast and prostate cancer; suicide and homicide. Between the end of the Depression and the end of World War II, income inequality in the U.S. declined appreciably, as did mortality rates among older Americans. During the same period, poverty decreased and welfare programs, such as Social Security, were instituted - factors which might also explain the decrease in elderly mortality rates. Rising national trends in heart disease were more consistent with trends in heart disease risk factors, such as smoking, than in income inequality. Trends in infant mortality and stroke were also inconsistent with national income inequality trends. However, trends in suicide and homicide were more compatible with income inequality trends, particularly between the Depression and the 1950s. The regions with the highest increases in income inequality from 1978 to 2000 also had the greatest reductions in total mortality. The authors did not find much evidence of significant regional variations in the relationship between income inequality and different causes of death.