To determine whether children with autism spectrum disorders (ASDs) have an increased number of wave I abnormal amplitudes in auditory brainstem responses (ABRs) than age- and sex-matched typically developing children. This analytical case-control study compared patients with ASDs between the ages of 2 and 6 years and children who had a language delay not associated with any other pathology. Amplitudes of ABR waves I and V; absolute latencies (ALs) of waves I, III, and V; and interpeak latencies (IPLs) I-III, III-IV, and I-V at 90 dB were compared between ASD patients and normally developing children. The study enrolled 40 children with documented ASDs and 40 age- and sex-matched control subjects. Analyses of the ABR showed that children with ASDs exhibited higher amplitudes of wave 1 than wave V (35%) more frequently than the control group (10%), and this difference between groups reached statistical significance by Chi-squared analysis. There were no significant differences in ALs and IPLs between ASD children and matched controls. To the best of our knowledge, this is the first case-control study testing the amplitudes of ABR wave I in ASD children. The reported results suggest a potential for the use of ABR recordings in children, not only for the clinical assessment of hearing status, but also for the possibility of using amplitude of ABR wave I as an early marker of ASDs allowing earlier diagnosis and intervention. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Autism Res 2017, 10: 1300-1305. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.