Objectives：The purpose of this study was to verify the validity and clinical cutoff score of the Child Behavior Checklist for ages 1.5-5 (CBCL 1.5-5) for diagnosis of autism spectrum disorder (ASD).

Methods：44 ASD infants and 100 normal infants participated. T-test, discriminant analysis, receiver operating characteristic (ROC) curve analysis, and odds ratio analysis were performed on the data.

Results：Discriminant validity was confirmed by mean differences and discriminant analysis on the subscales of Withdrawn, Attention problems, Internalizing problems, Externalizing problems, Total problems, and all Diagnostic and Statistical Manual of Mental Disorders (DSM)-oriented scales between the two groups. ROC curve analysis showed that Withdrawn, Attention problems, Internalizing problems, Externalizing problems, Total problems, DSM pervasive developmental problems, DSM attention deficit/hyperactivity problems, and DSM oppositional defiant problems significantly predicted ASD infants compared to normal infants. In addition, the clinical cutoff score criteria adopted in the Korean CBCL 1.5-5 for subscales of Withdrawn, Attention problems, Internalizing problems, Externalizing problems, Total problems, DSM pervasive developmental problems, DSM attention deficit/hyperactivity problems, and DSM oppositional defiant problems were shown to be valid.

Conclusion：The subscales of Withdrawn, Attention problems, Internalizing problems, Externalizing problems, Total problems, DSM pervasive developmental problems, DSM attention deficit/hyperactivity problems, and DSM oppositional defiant problems significantly discriminated for the diagnosis of ASD.