The proposed DSM-5 criteria for Autism Spectrum Disorder (ASD) depart substantially from the previous DSM-IV criteria. In this file review study of 131 children aged 2–12, previously diagnosed with either Autistic Disorder or Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), 63 % met the new DSM-5 ASD criteria, including 81 % previously diagnosed with Autistic Disorder and only 17 % of those with PDD-NOS. The proportion of children meeting DSM-5 differed by IQ grouping as well, with higher rates in lower IQ groups. Children who did meet criteria for ASD had significantly lower levels of cognitive and adaptive skills and greater autism severity but were similar in age. These findings raise concerns that the new DSM-5 criteria may miss a number of children who would currently receive a diagnosis.