This study examined racial differences in cardiac catheterization rates and reviewed whether patients' beliefs or other variables were associated with observed disparities. The authors performed a prospective observational cohort study of 1,045 white and African American patients at five Veterans Affairs (VA) medical centers whose nuclear imaging studies indicated reversible cardiac ischemia. There were few demographic differences between white and African American patients in the sample. African Americans were less likely than whites to undergo cardiac catheterization. African Americans were more likely than whites to indicate a strong reliance on religion and to report racial and social class discrimination. African Americans were less likely to indicate a generalized trust in people, but did not differ from white patients on numerous other attitudes about health and health care. Neither sociodemographic or clinical characteristics, nor patients' beliefs, explained the observed disparities, but physicians' assessments of the procedure's importance and patients' likelihood of coronary disease seemed to account for differences not otherwise explained. The study concluded that patients' preferences are not the likely source of racial disparities in the use of cardiac catheterization among veterans using VA care, but physicians' assessments warrant further attention.