Background: Autism is a complex developmental condition that typically manifests in the first three years of life. Objectives: detection of plasma level of (TGF-β2), (HSP70) and (IFN) γ in children with Autism Spectrum Disorder (ASD) and to find out correlation between their plasma levels and severity of ASD. Methodology: 40 children newly diagnosed with ASD recruited from Child Outpatients Clinics, Faculty of Medicine, Ain Shams University. All children were subjected to developmental history, prenatal, Physical and neurological examination, Cognitive age using Stanford Bine intelligence scale to exclude other mental or neurobehavioral disorders and laboratory detection of plasma level of HSP70, TGF-β2 and INF-γ by an ELISA kit. Results: HSP70 was (15.901±2.638), IFNγ was (92.37±7.893) and TGFβ2 was (68.7±8.39), conclusion: There was a negative correlation between the level of TGFβ2 and CARS while there were a positive correlation between the level of HSP70 and IFN-γ with CARS.