Three studies were designed to measure various indicators of the reliability and validity of the Preschool Behavior Screening System (PBSS) as a screening instrument for emotional and behavioral disorder risk status of children of preschool age. Study 1 and Study 2 served to establish evidence for content validity. Study 3 investigated one type of reliability evidence (i.e., internal consistency) and four types of validity evidence (i.e., internal structure validity, validity evidence based on external relations, concurrent validity, and cross-informant agreement).Teachers and parents of children (N = 113) enrolled in preschool and childcare programs completed Phase 1 and Phase 2 of the PBSS and the Behavior Assessment System for Children (BASC-2). Cross-informant agreement between parent and teacher ratings on the PBSS was generally moderate, and internal consistency was high. PBSS Phase 1 and PBSS Phase 2 were correlated in the expected directions, and sensitivity and negative predictive value were high. Results suggest that the PBSS may yield psychometrically sound scores for helping states meet child-find requirements. Directions for future development of the PBSS are provided.