The relation between ethnicity, socioeconomic position, and health is complex, has changed over time, and differs between countries. In the United States there is a long tradition of treating ethnic group membership simply as a socioeconomic measure, and differentials in health status between African Americans and groups of European origin have been considered purely socioeconomic. A contrary position sees the differences as either "cultural" or due to inherent "racial" differences. Although conventional socioeconomic indicators statistically explain much of the health difference between African Americans and Americans of European origin, they do not tell the full story. Incommensurate measures of socioeconomic position across ethnic groups clearly contribute to this difference. Additional factors, such as the extent of racism, are also likely to be important. The interaction of ethnicity, social position, and health in Britain is similarly complex. Studies that inadequately account for socioeconomic circumstances when examining ethnic-group differences in health can reify ethnicity (and its supposed correlates); however, the reductionist attribution of all ethnic differences in health to socioeconomic factors is untenable. The only productive way forward is through studies that recognize the contingency of the relations between socioeconomic position, ethnicity, and particular health outcomes.