Case identification of children with high-functioning pervasive developmental disorders (HFPDD) including Asperger's disorder tends to be delayed. A delay of case identification prevent from access to early intervention for children and parents. Although early diagnosis of HFPDD is difficult and less sensitive at present, several objective evaluation scales, such as CARS, ADOS-G and ADI-R, can be applied to very young children and are found to be relatively sensitive and stable. Recently autism-specific screening tools, such as the Checklist for Autism in Toddlers (CHAT), the Modified Checklist for Autism in Toddlers (M-CHAT), have been developed. The current research using the Japanese version of the M-CHAT and its clinical use combined with the infant health check-up system are described.