Eighty children, 3-17 years of age, with autism or Asperger syndrome and mild to severe distress in the presence of some sounds, were randomly allocated to two groups. The experimental group received auditory training and the control group listened to the same unmodified music under the same conditions. Significant improvements in behavior and severity of autism were maintained for 12 months by both groups. Informal data suggested that a range of abnormal responses to sound and other sensory abnormalities may also have improved. Verbal and performance IQ increased significantly 3 to 12 months after interventions. Findings suggest that some aspect of both auditory training and listening to selected unmodified music may have a beneficial effect on children with autism and sound sensitivity, and indicate a need for further research into the effects that led to these changes and the mechanisms involved in the sensory abnormalities commonly associated with autism.