Review of 78 evaluations for 29 young children examined practices used in assessment of autism spectrum disorders in three settings: public schools, developmental disabilities eligibility determinations, and our hospital-based early childhood mental health program. While similar rates of classification of autism spectrum disorders were found across sites, the rate of agreement by different evaluators for individual children was only 45%. Further, most community evaluators did not follow best practice guidelines nor use autism diagnostic tools with established psychometric properties. In this sample of primarily Latino, Spanish-speaking children, most community evaluators did not document assessment of the child in their native language, nor address the impact of language in their assessments.