Background: Black and Hispanic older Americans are less likely than white older Americans to possess advance directives. Understanding the reasons for this racial and ethnic difference is necessary to identify targets for future interventions to improve advance care planning in these populations. Methods: The aim of the study was to evaluate whether racial and ethnic differences in advance directive possession are explained by other demographic factors, religious characteristics, and personal health values. A general population survey was conducted in a nationally representative sample using a web-enabled survey panel of American adults aged 50 and older (n = 2154). Results: In a sample of older Americans, white participants are significantly more likely to possess advance directives (44.0%) than black older Americans (24.0%, p < 0.001) and Hispanic older Americans (29.0%, p = 0.006). Gender, age, retired or disabled employment status, educational attainment, religious affiliation, Internet access, preferences for physician-centered decision making, and desiring longevity regardless of functional status were independent predictors of advance directive possession. In fully adjusted multivariable models with all predictors included, black older Americans remained significantly less likely than white older Americans to have an advance directive (odds ratio [OR] = 0.42, 95% confidence interval [CI] = 0.24-0.75), whereas the effect of Hispanic ethnicity was no longer statistically significant (OR = 0.65, 95% CI = 0.39-1.1). Conclusion: In a nationally representative sample, black race is an independent predictor for advance directive possession. This association remains even after adjustment for other demographic variables, religious characteristics, and personal health values. These findings support targeted efforts to mitigate racial disparities in access to advance care planning.