The purpose of the research was to study the TTS values and latency of fifth wave Auditory Brainstem Response in human monaural and binaural fatigue, using auditory evoked potentials. From the results obtained in 12 volunteers, it is concluded that during exposure to auditory fatigue, if only one ear is protected, the unprotected ear is subject to a greater hearing loss than would be expected with both ears unprotected. The practical implication of these conclusions is that subjects with unilateral hearing loss occupationally exposed to noise run a greater risk for the healthy ear than subjects with normal hearing.