Several instruments have been developed to screen for autism spectrum disorders (ASD) in high-risk populations. However, few studies compare different instruments in one sample. Data were gathered from the "Early Screening of Autistic Traits Questionnaire," "Social Communication Questionnaire," "Communication and Symbolic Behavior Scales-Developmental Profile," "Infant-Toddler Checklist" and key items of the "Checklist for Autism in Toddlers" in 238 children (mean age = 29.6 months, SD = 6.4) at risk for ASD. Discriminative properties are compared in the whole sample and in two age groups separately (8-24 months and 25-44 months). No instrument or individual item shows satisfying power in discriminating ASD from non-ASD, but pros and cons of instruments and items are discussed and directions for future research are proposed.