This study examined the validity of the Korean version of the Child Behavior Checklist (K-CBCL) with 180 children with autism spectrum disorder (ASD) in South Korea. Rasch analysis was applied to examine item fit, item difficulty, suitability of the response scale, and person and item separation indices of the K-CBCL. The results indicated that, with the exception of six out of the 119 items, the K-CBCL had a good item fit. Suitability of the rating scale was supported. Both Attention Problems and Aggressive Behavior factors differentiated two strata of behavior problems of children with ASD, whereas six other factors only captured one stratum of behavior problems. The item separation index indicated that the items were distributed well with high reliability. We demonstrated that statistical item analysis with the Rasch model could provide valuable information related to psychometric properties.