The success of early intervention programs has in large part spurred increasing emphasis on identifying children with autism and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS) at the earliest possible ages. National and international professional groups have called for early screening and diagnosis, yet the technology to effectively meet these goals are insufficient. The Checklist for Autism in Toddlers (CHAT) and its variants is the only scale with acceptable psychometrics at present, but measures autism only. In this paper we describe a new measure, the Baby and Infant Screen for Children with aUtIsm Traits (BISCUIT), which is geared toward identifying young children with autism and PDD-NOS, and which also assesses for comorbid psychopathology and challenging behaviors. This initial study describes item selection and reliability for all three parts of the measure, which were individually administered to the parents of 276 children ages 17-37 months identified as at risk for developmental and/or physical disabilities. (Contains 3 tables.)