The aim of the study is to evaluate the effectiveness of the Social Communication Questionnaire (SCQ) to early recognize autistic spectrum disorder (ASD) patients with a comorbidity of attention deficit hyperactivity disorder (ADHD). The SCQ is a 40 items questionnaire developed as a screening tool for ASD in children, with yes/no questions (presence of symptoms with a score of 1/ absence of symptoms with a score of 0) and a risk cutoff. We have analyzed 75 questionnaires completed by both parents of the 75 children referred to the Child Neuropsychiatry Unit of the "Aldo Moro" University of Bari for a psychopathological assessment. These patients received a diagnosis of ASD with a comorbidity of ADHD (24) or without a comorbidity with ADHD (51). Results indicate a higher score of SCQ in patients with overlap diagnosis rather than patients with pure ASD. In particular, the items with a higher frequency are deficit in sociability, empathy and impulse control. Furthermore, patients with intellectual disabilities have a higher score. Findings highlight the use of the SCQ in the assessment of ASD population to early detect potential comorbidity with ADHD.