Early detection of autism spectrum disorder (ASD) facilitates early intervention, which improves lifelong prognosis. Universal screening in the medical home during toddler check-ups is successful at detecting many cases of ASD, yet uptake remains low, in part due to many barriers to successful ASD screening by pediatricians, including limited time and resources during the well-child visits, and low confidence in the screening process. In addition, underserved children from minority and low-income families are less likely to be screened compared to their White and middle-class peers, exacerbating the known disparities in access to early diagnosis and ASD intervention. The current proposal aims to expand beyond screening at pediatric well- visits, by developing and evaluating novel strategies to successfully screen for ASD in childcare centers, where many children spend more than 30 hours per week. Although there have been screening studies conducted in childcare centers, the feasibility of routinely using this alternate setting has not been widely addressed yet, and preliminary findings indicate that primary care strategies are not acceptable in childcare settings. Early Childhood Education Providers (ECEPs) have extensive exposure to normative child behavior and many hours of engagement with children, including many in underserved communities, enrolled in childcare. Thus, engagement of ECEPs in toddler screening could present an opportunity for significant improvement in ASD early identification and reduction of disparities in age of diagnosis and early treatment. However, there are existing barriers to autism screening in childcare centers, including low parental acceptance, which is critical to identify and address. Therefore, the goal of this pilot study is to explore barriers and facilitators of systematic screening by ECEPs, including cultural hesitancy, and using the strategies identified, examine the performance of the illustrated Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F) paired with the Ages and Stages Questionnaires in childcare centers. The specific aims are to: (1) utilize qualitative methods (field observations and semi-structured interviews) with ECEPs to investigate organizational barriers and facilitators for implementation of ASD screening in childcare setting, (2) utilize qualitative methods (semi- structured interviews) with disadvantaged parents of children attending childcare centers to investigate familial and cultural barriers and facilitators for parent engagement in screening for ASD in childcare centers serving underserved families, and (3) pilot novel strategies for ASD screening in childcare centers, informed by the qualitative findings, to evaluate agreement between parents and ECEPs, accuracy of childcare screening, and acceptability of ASD screening in childcare centers. Results of this proposed study will directly address a gap in universal ASD screening, particularly for unders...