Auditory brainstem response (ABR) is a good screening test for cerebellopontine angle (CPA) tumors and other retrocochlear diseases. The pathologic correlates of many cases with positive ABR remain unknown. A two-staged clinical study was performed to help us understand the significance of a false-positive ABR. In the first stage, data from 66 patients with abnormal ABR were reviewed. Nineteen patients had identifiable causes for the ABR abnormality, whereas 47 patients had no lesions identified. In the second phase of the study 21 of the 47 patients were re-evaluated with a minimum follow-up period of 1 year. A detailed interval history was obtained, and the work-up, including imaging studies, was repeated in an attempt to reach a diagnosis. One patient was found to have a CPA tumor, but for nine patients a definite final diagnosis could not be determined. The implications of abnormal ABR and normal initial imaging study are discussed, and a plan for the work-up of these patients is suggested.