This article considers the ways in which race/ethnicity and socioeconomic status (SES) relate to each other and combine to affect racial variations in health status. The author reviews a number of methodological issues concerning the assessment of race in the United States that importantly affect the quality of the available data on racial differences in health. These issues include the discrepancy between self-identification and observer-reported race, changing racial classification categories and racial identification, the difficulties in categorizing persons of mixed racial parentage, and census undercount. In discussing the complex interactions between race and SES, the author first describes the relationship between race and SES and assesses the role of SES in accounting for racial differences in health, then shows how the failure of SES to completely account for racial variations in health status emphasizes the need for health researchers to give more systematic attention to the unique factors linked to race that affect health. These factors include racism, migration, acculturation, and the comprehensive assessment of SES.