Vineland Adaptive Behavior Scales (VABS) data were examined in a large sample of young children with ASD (n = 290) of varying cognitive levels. IQ was higher than VABS composite score among high functioning children only; the opposite pattern was found in lower IQ subgroups. Profile analysis of VABS domains across cognitive levels demonstrated different profiles in different subgroups. A characteristic "autism profile" was found for most subgroups for Age Equivalents but not Standard Scores. In a small set of matched pairs (n = 28) of children with autism versus MR, significantly different profiles were found, with Socialization and Communication lower in autism, but no differences were found between matched pairs of children with autism and PDD-NOS (n = 48). Correlations between age, cognitive level, and adaptive level were also reported, and regression analyses indicated that autism severity accounts for a modest amount of unique variance in Socialization and Daily Living Skills.