Given the emphasis on early screening for ASD, it is crucial to examine the concordance between parent report and clinician observation of autism-related behaviors. Similar items were compared from the First Year Inventory (Baranek et al. First-Year Inventory (FYI) 2.0. University of North Carolina, Chapel Hill, 2003), a parent screener for ASD, and the ADOS-2 Toddler Module (Lord et al. 2013), a standardized ASD diagnostic tool. Measures were administered concurrently to 12-month-olds at high and low risk for ASD. Results suggest that clinicians and parents rated behaviors similarly. In addition, both informants rated high-risk infants as more impaired in several social-communication behaviors. Furthermore, the format of questions impacted agreement across observers. These findings have implications for the development of a new generation of screening instruments for ASD.