Blacks in the U.S. not only report experiencing more racism than other racial and ethnic groups, but also have a higher prevalence of hypertension, with subsequent greater hypertension-related mortality, compared to Whites (Healthy People 2010, 2001). Racism can occur on multiple levels, including cultural, institutional, and interpersonal (C.P. Jones, 2000; J. M. Jones, 1997; Krieger, 1999). Membership in a stigmatized racial or ethnic (minority) group may contribute to the higher prevalence of hypertension among U.S. Blacks (Brondolo, Rieppi, Kelly, & Gerin, 2003). To explain this potential relationship, researchers have posited that perceived racism is a chronic, stressful stimulus that negatively influences health outcomes by chronic overactivity of cardiovascular regulatory systems (R. Clark, Anderson, Clark, & Williams, 1999; Mays, Cochran, & Barnes, 2007; McEwen, 2002). Researchers have suggested that racial identity may influence the relationship of racism to blood pressure. However, most research on racial or ethnic identity has examined the ways in which it acts as an antecedent or correlate of mental health, or how it moderates or mediates the relationship between perceived racism and mental health. A subsample (n = 214) of U.S. born, adult Black participants from a larger study of Racism, Coping, and Ambulatory Blood Pressure. Participants completed the Lifetime and Past Week Perceived Racism scales of the Perceived Ethnic Discrimination-Community Version Questionnaire (Brondolo et al., 2005), the Multigroup Ethnic Identity Measure (Phinney, 1992), and they were also outfitted with an ambulatory blood pressure monitor (ABP) and electronic diary to assess blood pressure for a 24 hr period. Three models of racial-ethnic identity were compared to understand how it is related to the association between perceived racism and ABP. Lifetime perceived racism was related to nighttime systolic blood pressure. However, there was no relationship of perceived racism to ethnic identity and no relationship of ethnic identity to ABP. Ethnic identity did not moderate the relationship of perceived racism to ABP. This study highlights the need for further research using ecological momentary assessment and specifically, real-time measures of perceived racism and ethnic identity using repeated measures sampling.