To determine if the loud noise generated by magnetic resonance (MR) imaging equipment is capable of inducing hearing loss, the hearing of 24 patients was tested before and after MR imaging. Fourteen patients were imaged without ear protection, and six (43%) suffered a temporary, mild loss of hearing (less than or equal to 15 dB at at least one frequency). Ten patients were imaged with ear protection, and only one experienced any hearing loss. Therefore, the noise generated by MR imagers may cause temporary hearing loss, and earplugs can prevent this loss. All threshold changes had returned to within 10 dB of baseline by 15 minutes after completion of the second audiometric test.