Socioeconomic status is considered by many to be a fundamental cause of disease and death. In this paper, we document educational and income inequalities in all-cause and cause-specific mortality at ages 35-64 in Finland and the United States, two countries with different health care systems, income distributions, and social welfare programs for the working-age population. We found that education is an independent determinant of premature mortality for men and women in both countries after adjustment for age, household size, family income, marital status, and labor force participation. Educational inequalities in mortality in both places were most pronounced for causes of death that were linked to health behaviors, risk-taking behaviors, and stress. These educational inequalities were largest for Finnish men, for whom the association between education and mortality was linear. For Finnish women and for American men and women educational thresholds mattered more than each additional year of schooling. The association between family income and mortality was curvilinear in both countries. The degree of curvature was more pronounced in the United States than in Finland when family-income effects were adjusted only for age and household size. When we also controlled for education, labor force participation, and marital status the income effects were strongly attenuated and the difference in curvature between countries was no longer statistically significant. That increases in family income were more important for reducing mortality at the lower end of the income distribution in both countries suggests that there are diminishing returns to family income, and poverty is detrimental to health. The findings suggest that effects of an individual's socioeconomic position on mortality, whether measured by education or family income, are to a large extent independent of how society is organized.