OBJECTIVES: We examined agreement of administrative data with self-reported race/ethnicity and identified correlates of agreement. METHODS: We used Veterans Affairs administrative data and VA 1999 Large Health survey race/ethnicity data. RESULTS: Relatively low rates of agreement (approximately 60%) between data sources were largely the result of administrative data from patients whose race/ethnicity was unknown, with least agreement for Native American, Asian, and Pacific Islander patients. After exclusion of patients with missing race/ethnicity, agreement improved except for Native Americans. Agreement did not increase substantially after inclusion of data from individuals indicating multiple race/ethnicities. Patients for whom there was better agreement between data sources tended to be less educated, non-solitary living, younger, and White; to have sufficient food; and to use more inpatient Department of Veterans Affairs (VA) care. CONCLUSIONS: Better reporting of race/ethnicity data will improve agreement between data sources. Previous studies using VA administrative data may have underestimated racial disparities.