Purpose of the article: Autism spectrum disorder (ASD)is an impairing neurodevelopmental disorder with an unknown etiology. The present study aims to investigate if the auditory brainstem response (ABR)to complex stimuli in children and adolescents diagnosed with ASD can be a possible objective biomarker in autism. Materials and methods: The ABR of 39 youth with ASD (7–18 years)were compared to the ABR of 34 typically developed youth (TD). The ABR consists of seven positive peaks (waves I–VII)that occur during 10 Ms following a sound stimulus. Results: The amplitude of wave III (region 2.5–4.0 Ms)was higher in the ASD group compared to the TD group. The TD males showed a significant lower degree of correlation, between left and right ear compared to the ASD groups and the TD females. Conclusions: Altered auditory processing was evident in the pons region of the brainstem for the ASD group when compared to the TD group. Implications of the findings are discussed in relation to the neurobiology and assessment of autism spectrum disorder in youth.