Sudden hearing loss is a reduction of sensoneurinal sound perception with a sudden onset. It is usually occurring only in one ear and without a recognizable cause. If a hearing loss is suspicioned due to otoscopic and tuning fork test findings, the patient should rapidly be sent to an ENT-specialist because of the possible consequences. After the first examinations by means of ear microscopy and audiogram further diagnostics may be necessary. If no cause is found, the idiopathic sensorineural hearing loss remains as the exclusion diagnosis. Therapy follows a polypragmatic approach based on the different theories of its origin. Therefore mainly antiinflammatory, antiviral and vasoactive drugs are applied. The high spontaneous healing rate and the still pending proof of effectiveness of all types of therapy used so far must be considered.