Objectives: Hearing loss should not be a limiting factor in children with autism. There are no investigations that assesed the incidence of this problem in Latin America. In fact, even when accepted in specialized institutions, children don′t receive programmed evaluation of hearing. We set this research to assess the incidence and causes of hearing loss in Chilean children with autism, as a representative of the situation in developing countries. Methods: Patients ranging from 3 to 13 years were evaluated for hearing loss using the following parameters: personal and medical history, physical examination, otoacustic emissions, tympanogram, auditory reflexes, and playing audiometry. As a result of the previous evaluation, hearing was classified as normal, conductive hearing loss, or sensorineural hearing loss. Cause of the alteration was determined. Patients suceptible for treatment were treated and evaluated posteriorly. Results: Seventy-two of 74 patients were evaluated; 24 were found to have a cause of hearing loss. Sixty-seven percent were bilaterally affected; 79% were found to have conductive hearing loss; and 21% had senorineural hearing loss. We found several tractable causes for conductive hearing loss and they received appropiate treatment. Cases of sensorineural hearing loss were found to have characteristics of cortipathy, and appropiate follow-up was established. Conclusion: Children with autism are perfectly able to receive audiologic evaluation. We found that an important proportion of children with autism (32%) do have a cause of hearing loss, and more importantly, in the majority of cases this can be treated easily. Rational programs of diagnosis and follow-up must be set in institutions.