ABSTRACT.Objective. More than half of Medicaid enrollees are now in managed care. Scant information exists about which policies of practice sites improve quality of care in managed Medicaid. Children with asthma are a sentinel group for Medicaid quality monitoring because they are at elevated risk for adverse outcomes. The objective of this study was to identify practice-site policies and features associated with quality of care for Medicaid-insured children with asthma.Methods. A prospective cohort study with 1-year follow-up was conducted in 5 health plans in California, Washington, and Massachusetts. Data were collected via telephone interviews with parents at baseline and 1 year, surveys of practice sites and clinicians, and computerized databases. The practice site survey asked about policies to promote cultural competence, the use of several types of reports to clinicians, support for self-management of asthma, case management and care coordination, and access to and continuity of care. Quality of care was evaluated on the basis of 5 measures: 1) preventive medication underuse based on parent report; 2) the parent's rating of asthma care; 3) the 1-year change in the child's asthma physical status based on a standardized measure; 4) preventive medication underprescribing based on computerized data; and 5) the occurrence of a hospitalbased episode.Results. Of the 1663 children in the study population, 67% had persistent asthma at baseline based on parent report of symptoms and medications. At 1-year followup, 65% of the children with persistent asthma were underusing preventive medication based on parent report. In multivariate analyses, patients of practice sites with the highest cultural competence scores were less likely to be underusing preventive asthma medications based on parent report at follow-up (odds ratio Poor and minority children are at elevated risk for asthma hospitalization, and many do not receive appropriate outpatient treatment. [1][2][3][4] In general, Medicaid-insured children may receive worse care than privately insured children, even when they are in the same health plans. 5 Scant information exists to help clinicians and policy makers understand how to improve health care quality effectively for children in managed Medicaid arrangements. 6 Clinicians who treat Medicaid-insured children need better information about which practice-site policies most enhance quality of care for this vulnerable group. Three general categories of practice-site policies are those that are tailored to low-income populations, chronic care policies, and primary care elements. Policies that are tailored to low-income populations attempt to promote cultural competence, 7-9 communication, and empowerment. Policies described in the Chronic Care Model include self-management support, decision support, clinical information systems, delivery system design, health care organization, and community resources. 10 Primary care elements have been defined as first-contact care (commonly called access), longitudinality (...