The tecnique that we use for eliciting brainstem auditory evoked responses (BAERs) is described. BAERs are a non-invasive and reliable clinical test when carefully performed. This test is indicated in the evaluation of disorders which may potentially involve the brainstem such as coma, multiple sclerosis posterior fossa tumors and others. Unsuspected lesions with normal radiologic studies (including CT-scan) can be revealed by the BAER.