We tested the ability of the 2001 CBCL syndromes to discriminate among 86 children with Autism Spectrum Disorder (ASD), 117 children with Attention Deficit Hyperactivity Disorder-Inattentive type, 426 children with Attention Deficit Hyperactivity Disorder-Hyperactive-Impulsive or Combined type, 200 clinically referred children who did not receive a diagnosis, and 436 typically-developing children in a community sample. The Withdrawn/Depressed, Social Problems, and Thought Problems syndromes significantly discriminated the ASD group from the four other groups. An ASD scale, constructed from nine CBCL items, demonstrated moderate to high sensitivity (68 to 78%) and specificity (73 to 92%). Consistent with previous research, findings from this study provide strong support for the CBCL as a screening tool for ASD.