The present invention relates to a composition for preventing or treating hearing loss, containing an HMG-CoA reductase inhibitor and, more specifically, to a composition for preventing or treating diabetes-mediated hearing loss, containing, as an active ingredient(s), one or more types selected from the group consisting of atorvastatin, fluvastatin, lovastatin, pitavastatin, pravastatin, rosuvastatin and simvastatin. A pharmaceutical composition containing an HMG-CoA reductase inhibitor, according to the present invention, inhibits auditory cell death caused by diabetes, and thus is very useful as an agent for preventing or treating diabetes-mediated sensorineural hearing loss.