Our study examines associations between race and ethnicity and hospitalization for ambulatory care sensitive (ACS) conditions for working age adults, and for individuals age 65 or older. We use ACS hospitalization as an outcome indicator to evaluate access to primary care. The prevalence of ACS conditions in the population, including those not hospitalized, and the occurrence of ACS and non-ACS hospitalization, are estimated using nationally representative data from the 1997 US Medical Expenditure Panel Survey. We calculate population-based relative rates of ACS hospitalization using the 1997 Nationwide Inpatient Sample, a large sample of United States' community hospitals, and the US Census. We investigate the sensitivity of these relative rates to the inclusion of conditions for which hospitalization varies notably across areas, and adjust the rates for both underlying hospitalization patterns for non-ACS conditions, and for disease prevalence in the population groups studied. The analyses consistently show that African Americans and Hispanics have significantly higher rates of ACS hospitalization than non-Hispanic whites. This result applies to women and men, and both age groups studied. These higher rates persist after adjusting for disease prevalence and non-ACS admission rates, and for the inclusion of high variation conditions.