Objective: This study aimed to identify autistic like traits in relatives of patients with schizophrenia and autism spectrum disorder. Method: causal-comparative research design was utilized. Fifty individuals among the first degree relatives of patients with autism spectrum disorder and 50 individuals among the first degree relatives of patients with schizophrenia spectrum disorder were selected. Autistic-like traits were evaluated by Autism-Spectrum Quotient (AQ). Multivariate analysis of variance was used to compare the autistic like traits in two groups. Results: First degree relatives of individuals with autism spectrum disorder got higher scores in deficiency of social skill, deficiency of communication, deficiency of attention, and attention to details. As well as they got lower scores in deficiency of imagination, in comparison to relatives of individuals with schizophrenia spectrum disorder. Conclusion: Relatives of individuals with autism spectrum disorder compared to relatives of patients with schizophrenia spectrum disorder showed higher rates of autistic like traits. Only the exception was imagination subscale.