The sensory cells of the inner ear are vulnerable to several agents (aminoglycosides, cytostatics, ionizing irradiation). The effect of strong magnetic fields occurring in industries with production based on electrolytic processes and with medical magnetic resonance equipment is unknown. The aim of this study was to clarify the effect of strong static magnetic fields on the inner ear, by exposing 11 healthy men to a magnetic field with flux density of 2-7 mT for 9 h. No damage was found to the acoustic or vestibular system.