The objective of this study was to assess the internal construct validity of the DSM-IV as a conceptual model for characterizing behavioral syndromes in children with ASD. Parent and teachers completed the Child Symptom Inventory-4, a DSM-IV-referenced rating scale, for 6-to-12 year old clinic referrals with an ASD (N = 498). Ratings were submitted to confirmatory factor analysis and models were assessed for fit. Results were also compared to those obtained for a sample of non-ASD psychiatric outpatient school-age children. Fit indices ranged from acceptable to good for the ASD samples and compared well to those obtained in typically developing children. Findings lend support to the notion that DSM-IV syndromes may be an appropriate conceptual model for characterizing psychopathology in ASD.