BACKGROUND: Little is known about the healthcare experiences of Medicare beneficiaries in Puerto Rico. OBJECTIVES: We compare the experiences of elderly Medicare beneficiaries in Puerto Rico with their English-preferring and Spanish-preferring Medicare counterparts in the U.S. mainland. RESEARCH DESIGN: Linear regression models compared mean Consumer Assessment of Healthcare Providers and Systems scores for these groups, using cross-sectional data from the 2008 Medicare Consumer Assessment of Healthcare Providers and Systems survey. SUBJECTS: Medicare beneficiaries aged 65 years and older (6733 in Puerto Rico, 282,654 in the U.S. mainland) who completed the 2008 Medicare Consumer Assessment of Healthcare Providers and Systems survey. MEASURES: Six composite measures of beneficiary reports and two measures of beneficiary-reported immunization. RESULTS: Beneficiaries in Puerto Rico reported less positive experiences than both English-preferring and Spanish-preferring U.S. mainland beneficiaries for getting needed care, getting care quickly, and immunization (P<0.05 in all cases). Beneficiaries in Puerto Rico reported better customer service than Spanish-preferring U.S. mainland beneficiaries and better doctor communication experiences than English-preferring U.S. mainland beneficiaries. Additional analyses find little variation in care experiences within Puerto Rico by region, plan type, or specific plan. CONCLUSIONS: Medicare beneficiaries in Puerto Rico report generally worse healthcare experiences than beneficiaries in the U.S. mainland for several Consumer Assessment of Healthcare Providers and Systems outcomes and lower immunization rates. Lower funding of healthcare services in Puerto Rico relative to the U.S. mainland may affect healthcare. Strategies such as patient and provider education, provider financial incentives, and increased use of information technologies may improve adherence to the recommended preventive care practices. Copyright © 2012 by Lippincott Williams & Wilkins.