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.