Administrative data result from administering health plans--tracking service utilization, paying claims, monitoring costs and quality--and have been used extensively for health services research. This article examines the strengths and limitations of administrative data for health services research studies of people with disabilities. Administrative data offer important advantages: encompassing large populations over time, ready availability, low cost, and computer readability. Questions arise about how to identify people with disabilities, capture disability-related services, and determine meaningful health care outcomes. Potentially useful administrative data elements include eligibility for Medicare or Medicaid through Social Security disability determinations, diagnosis and procedure codes, pharmacy claims, and durable medical equipment claims. Linking administrative data to survey or other data sources enhances the utility of administrative data for disability studies.