This paper presents evidence on the performance of Medicaid managed care organizations (MCOs) in providing Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) services to children under age 21. States face considerable challenges in integrating EPSDT into managed care. For example, MCOs rarely offer all services required under federal law. Also, MCOs often are unable to meet state reporting requirements. On the other hand, MCOs offer children a medical home, often for the first time, that may encourage timely preventive care. The literature generally shows no differences in the performance of MCOs relative to traditional FFS providers in the EPSDT participation rate. Future needs include improving the specificity of contract language, more precisely defining the EPSDT benefit package, evaluating the adequacy of EPSDT payments, monitoring the capacity of MCO provider networks, establishing the effectiveness of outreach and enabling services, developing standardized MCO reporting requirements, documenting program outcomes, and assessing benchmarks for accountability.