This study examined the phenotypic overlap between core diagnostic features and emotional/behavioral problems in a sample of 335 preschool children with autism spectrum disorder (ASD). Results from principal component analysis (2 components; 49.70% variance explained) suggested substantial phenotypic overlap between core diagnostic features and emotional/behavioral problems. Component I, Emotional Behavioral Repetitive Problems, was independent of the children's intellectual, adaptive functioning, and structural language abilities. Component II, Social Communication Deficits, was negatively related to the children's intellectual, adaptive functioning, and structural language abilities. Both components were positively related to parental stress. This exploratory study contributes to our understanding of the ASD phenotype and provides further support for including emotional/behavioral problems as part of the clinical characterization of children with ASD.