Context.–A prominent hypothesis regarding social inequalities in mortality is that the elevated risk among the socioeconomically disadvantaged is largely due to the higher prevalence of health risk behaviors among those with lower levels of education and income. Objective.–To investigate the degree to which 4 behavioral risk factors (cigarette smoking, alcohol drinking, sedentary lifestyle, and relative body weight) explain the observed association between socioeconomic characteristics and all-cause mortality. Design.–Longitudinal survey study investigating the impact of education, income, and health behaviors on the risk of dying within the next 7.5 years. Participants.–A nationally representative sample of 3617 adult women and men participating in the Americans' Changing Lives survey. Main Outcome Measure.–All-cause mortality verified through the National Death Index and death certificate reviews. Results.–Educational differences in mortality were explained in full by the strong association between education and income. Controlling for age, sex, race, urbanicity, and education, the hazard rate ratio of mortality was 3.22 (95% confidence interval [CI], 2.01 -5.16) for those in the lowest-income group and 2.34 (95% CI, 1.49-3.67) for those in the middle-income group. When health risk behaviors were considered, the risk of dying was still significantly elevated for the lowest-income group (hazard rate ratio, 2.77; 95% CI, 1.74-4.42) and the middle-income group (hazard rate ratio, 2.14; 95% CI, 1.38-3.25). Conclusion.–Although reducing the prevalence of health risk behaviors in low-income populations is an important public health goal, socioeconomic differences in mortality are due to a wider array of factors and, therefore, would persist even with improved health behaviors among the disadvantaged. JAMA. 1998;279:1703-1708; Higher mortality rates in low-income groups may not be entirely due to a higher rate of risky behaviors. Researchers analyzed data from 3,617 men and women participating in the Americans' Changing Lives survey. Income was strongly linked to mortality, with the risk of mortality higher in low-income groups compared to middle- and upper-income groups. Even after accounting for risky behaviors such as smoking, alcohol use, a sedentary lifestyle and obesity, the low-income group still had higher mortality rates.