OBJECTIVE: To examine the extent to which racial/ethnic differences in Consumer Assessment of Health Plans Study (CAHPS) ratings and reports of Medicaid managed care can be attributed to differential treatment by the same health plans (within-plan differences) as opposed to racial/ethnic minorities being disproportionately enrolled in plans with lower quality of care (between-plan differences). DESIGN: Data are from the National CAHPS Benchmarking Database (NCBD) 3.0. Data were analyzed using linear regression models to determine the overall effects, within-plan effects, and between-plan effects of race/ethnicity and language on patient assessments of care. Standard errors were adjusted for nonresponse weights and the clustered nature of the data. PATIENTS/PARTICIPANTS: A total of 49,327 adults enrolled in Medicaid managed care plans in 14 states from 1999 to 2000. MAIN RESULTS: Non-English speakers reported worse experiences compared to those of whites, while Asian non-English speakers had the lowest scores for most reports and ratings of care. An analysis of between-plan effects showed that African Americans, Hispanic-Spanish speakers, American Indian/ Whites, and White-Other language were more likely than White-English speakers to be clustered in worse plans as rated by consumers. However, the majority of the observed racial/ ethnic differences in CAHPS reports and ratings of care are attributable to within-plan effects. The ratio of between to within variance of racial/ethnic effects ranged from 0.07 (provider communication) to 0.42 (health plan rating). CONCLUSIONS: The observed racial/ethnic differences in CAHPS ratings and reports of care are more a result of different experiences with care for people enrolled in the same plans than a result of racial/ethnic minorities being enrolled in plans with worse experiences. Health care organizations should engage in quality improvement activities to address the observed racial/ethnic disparities in assessments of care.