This study explored the claim that individuals with autism and Asperger's disorder tend to process locally rather than holistically. Participants observed a large or "global" number composed of smaller or "local" numbers. The response was contingent upon the identification of either the large stimulus or the small stimuli. Relative to age, sex, and IQ matched controls, global processing in children and adolescents with autism (N = 12) and Asperger's disorder (N = 12) was more vulnerable when the local stimuli were incongruent. The autism group made more global errors than their matched control group, regardless of whether there was local incongruence. In contrast, the Asperger's disorder group made a similar number of global errors as their respective control group. These results were discussed in relation to an "absence of global precedence" notion, "weak central coherence" theory, and right-hemisphere dysfunction. The neurobiological significance of these findings were discussed in the context of a fronto-striatal model of dysfunction.