Background: Autism Spectrum Disorder (ASD) is a behaviorally defined complex neurodevelopmental syndrome. ASD is one of the most common child psychiatric disorders. Despite the long history of research on ASD, no much is known yet about the exact biological causes and how the disorder can be effectively treated. Objective: To study clinical effect of repetitive Transcranial Magnetic Stimulation (rTMS) on a sample of children with autism spectrum disorder. Patients and Methods: the sample consisted of 30 children. Their ages ranged from 4 to 10 years old. After being diagnosed clinically according to DSM-5 through a designed semi-structured interview and through application of childhood autistic rating scale CARS and assessment of the degree of clinical severity of autism spectrum disorders according to DSM-5. Results: The results of the study after the completion of 12 sessions of rTMS, there was a significant difference and improvement in the severity of the clinical symptoms for ASD except for the level of activity and listening response and use of the body by comparing the severity of symptoms before and after rTMS. Comparing results before and after rTMS by the level of clinical severity of autism according to DSM-5; at the level of severity in social communication, the improvement was statistically significant (p-value 0.001). At the level of severity in restricted and repetitive behaviors the improvement was statistically highly significant (p-value <0.001). Conclusion: this study concluded that rTMS over left dorso-lateral prefrontal cortex may be safe and effective way of providing a relief of ASD symptoms.