Although it is well known that informants often disagree about the degree of psychopathology in children, this issue has not been systematically evaluated in children with autism. The objective of this paper is to estimate the extent of agreement between parents and teachers on the assessment of autistic symptoms and adaptive behavior skills. We assessed 83 children, 4-6 years of age, with a diagnosis of pervasive developmental disorder (PDD), using the Autism Behavior Checklist (ABC) and the Vineland Adaptive Behavior Scales (VABS). Parents and teachers rated each child on each measure. While there was good agreement between informants on the VABS, teachers tended to rate the PDD children higher than parents. In contrast, there was virtually no agreement on the ABC. High levels of stress experienced by parents appeared to be associated with parents reporting more autistic behaviors and less adaptive skills than teachers. As with other child psychiatric disorders, caution must be exercised in combining information from several informants.