Vineland Adaptive Behavior Scales Special Population norms are presented for four groups of individuals with autism: (a) mute children under 10 years of age; (b) children with at least some verbal skills under 10 years of age; (c) mute individuals who are 10 years of age or older; and (d) individuals with at least some verbal skills who are 10 years of age or older. The sample included 684 autistic individuals ascertained from cases referred for the DSM-IV autism/PDD field trial collaborative study and five university sites with expertise in autism. Young children had higher standard scores than older individuals across all Vineland domains. In the Communication domain, younger verbal children were least impaired, older mute individuals most impaired, and younger mute and older verbal individuals in the midrange. Verbal individuals achieved higher scores in Daily Living Skills than mute individuals. The expected profile of a relative weakness in Socialization and relative strength in Daily Living Skills was obtained with age-equivalent but not standard scores. Results high-light the importance of employing Vineland special population norms as well as national norms when evaluating individuals with autism.