The federal Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) program requires mental health screening of Medicaid-eligible children as part of primary care medical assessments. However, decisions related to selection of a screening tool remain with the states. States need access to brief, cost effective, easily administered screening tools to comply with these regulations. This paper examines the psychometric properties of the Pediatric Symptom Checklist (PSC) reported on 6,590 children ages 6-22 enrolled in Florida's Medicaid program across seven areas of the state, whose caregivers participated in a mail survey at least once between 1998 and 2007. Results suggest the PSC has both good internal consistency and stability over time across children with varying health and mental health conditions. The PSC demonstrated excellent discriminant validity regarding its ability to differentiate among children with varying levels of disabilities. Evidence of the PSCs construct validity was found based on its significant associations with other measures in predicted directions. At the recommended cut-off score of 28, the PSC exhibited good sensitivity, specificity, positive predictive value, and negative predictive value. Collectively, these findings support the use of the PSC as an appropriate measure for screening the psychosocial needs of children enrolled in Medicaid. (Contains 3 tables.)